vtluu
03-21-2004, 04:31 AM
The Schroth AutoControl harness belt I ordered from HMS Motorsport (http://www.hmsmotosport.com/) (a close-out special, $50 instead of the $200 or so the AutoControl usually goes for) arrived a couple days ago and today I set about installing it. What follows is a detailed step-by-step instruction of the installation process I used. Other harness belts will have similar installation procedures, save perhaps the wiring which is required for the AutoControl.
Kit Contents
http://www.norcalevo.net/gallery/albums/album75/001s.jpg (http://www.norcalevo.net/gallery/albums/album74/001_G.jpg)
The AutoControl features a powered retractor mechanism (upper-left) that locks the tail strap unless a current is applied to it. The sensor unit (yellow) is basically a motion/tilt-sensitive switch that is open when tilted or when it encounters g-forces (acceleration/braking/turning). For this reason it should be installed with the car on level ground; my garage tilts forward ever so slightly so I rolled the car partway up a ramp to level it. The kit includes a bubble-type level so you can ensure the sensor is correctly installed.
Belt Installation
Obviously the chest/shoulder belts go through the holes in the Recaro seat. Contrary to the instructions, I started in front of the seat, threaded the belt through the right-side hole, then back through the left-side hole, because the buckle mechanism would not fit through the hole. Double-check to make sure the belt isn't backwards; the red button on the buckle should face the front of the car.
The left mounting bolt for the lap belt, which is the normally the bolt that holds the factory belt, hidden by a rubber cover that easily slides off. The bolt does not move with the seat, so slide the seat forward to make reaching the bolt easier. The bolt is tightly torqued but otherwise unscrews fairly easily.
http://www.norcalevo.net/gallery/albums/album75/014s.jpg (http://www.norcalevo.net/gallery/albums/album74/014_G.jpg)
Figure out which way the lap belt needs to be bolted on. To prevent confusion when bolting the anchor, I used a felt marker to designate the side of the anchor point that faces outwards--towards the head of the bolt. Also, I fount it necessary to bend the anchor point slightly for a better fit.
http://www.norcalevo.net/gallery/albums/album75/016s.jpg (http://www.norcalevo.net/gallery/albums/album74/016_G.jpg)
This is the bolt with both the Schroth and factory belt anchors on it, along with the factory spaces and washers. At this point, I double-checked there weren't any twists in the belt.
http://www.norcalevo.net/gallery/albums/album75/017s.jpg (http://www.norcalevo.net/gallery/albums/album74/017_G.jpg)
Before putting the bolt back in, I found it useful to slide the rubber cover forward as much as possible, as doing so with the bolt tightened was much more difficult.
Now for the right-side bolt: unlike the left, it moves with the seat and is very close to the center console. It was much easier to reach--working from behind the seat--after sliding the seat all the way back.
http://www.norcalevo.net/gallery/albums/album75/018s.jpg (http://www.norcalevo.net/gallery/albums/album74/018_G.jpg)
Also, I needed to partly remove the rear part of the center console; I undid these two screws at the bottom of the CD cubbyhole and flipped the console up to reach the anchor bolt.
http://www.norcalevo.net/gallery/albums/album75/020s.jpg (http://www.norcalevo.net/gallery/albums/album74/020_G.jpg)
As with the left anchor, I marked the "outside" face of the right anchor so I would know I had it facing the right way. Here's the bolt with the factory and Schroth anchors on it; again, before attaching the bolt I made sure the belt wasn't twisted.
http://www.norcalevo.net/gallery/albums/album75/021s.jpg (http://www.norcalevo.net/gallery/albums/album74/021_G.jpg)
Retractor/Tail Installation
I attached the retractor using the bolt for the factory shoulder belt for the left-most rear passenger. The first thing I did was remove the rear seat, which facilitates removing the trim and will be needed later to route the wiring. The rear seat comes in two pieces, the lower "bench" and the upper seat back. Reaching under the front of the bench you'll find two plastic pull tabs; pulling on these will release the hooks that are the only thing holding the bench in place. With the bench removed you can see the three bolts that you need to undo to remove the seat back. Presto!
http://www.norcalevo.net/gallery/albums/album75/103s.jpg (http://www.norcalevo.net/gallery/albums/album74/103_G.jpg)
http://www.norcalevo.net/gallery/albums/album75/104s.jpg (http://www.norcalevo.net/gallery/albums/album74/104_G.jpg)
Next, I removed the trim piece behind the back seat. First, I removed the plastic covers from the left and right C-pillars: grasp and pull steadily until the plastic claws release. Then, I undid child-seat anchor bolts:
http://www.norcalevo.net/gallery/albums/album75/105s.jpg (http://www.norcalevo.net/gallery/albums/album74/105_G.jpg)
The speaker grilles hold the trim piece in place as well, so they had to be removed. The plastic anchors holding them in place (three on each grille) are easily accessed through the trunk; I undid them by using pliers to tuck in the "barbs" and push the anchors through.
http://www.norcalevo.net/gallery/albums/album75/106s.jpg (http://www.norcalevo.net/gallery/albums/album74/106_G.jpg)
Next, I undid the five light-blue plastic anchors (one shown below) that directly attach the trim to the frame.
http://www.norcalevo.net/gallery/albums/album75/107s.jpg (http://www.norcalevo.net/gallery/albums/album74/107_G.jpg)
A photo of the trim piece removed gives a better view of the position of the anchors:
http://www.norcalevo.net/gallery/albums/album75/108s.jpg (http://www.norcalevo.net/gallery/albums/album74/108_G.jpg)
For these anchors, I used a screwdriver with a small socket head attached which I would push up against the anchor; the socket would tuck in the barbs holding the anchors in place.
http://www.norcalevo.net/gallery/albums/album75/109s.jpg (http://www.norcalevo.net/gallery/albums/album74/109_G.jpg)
The last thing holding the trim piece in place was the third brake light, which I easily removed by unscrewing two bolts (accessed from the trunk) and disconnecting the light from its harness.
http://www.norcalevo.net/gallery/albums/album75/110s.jpg (http://www.norcalevo.net/gallery/albums/album74/110_G.jpg)
The trim piece should now come off. Peeling back the rubbery sound insulation reveals the belt anchor bolt we're after.
http://www.norcalevo.net/gallery/albums/album75/111s.jpg (http://www.norcalevo.net/gallery/albums/album74/111_G.jpg)
I now needed to put a hole in the trim cover so that I could poke a new, longer bolt through. To figure out where on the trim piece to drill, I removed the factory bolt, temporarily put the insulation and trim piece back in place, and used a long thin drill bit through the bolt-hole (again, accessed from the trunk) to poke a small guide hole through the sound insulation and trim piece (which is made of wooden pressboard).
http://www.norcalevo.net/gallery/albums/album75/112s.jpg (http://www.norcalevo.net/gallery/albums/album74/112_G.jpg)
Using the guide hole, I cut larger holes in the sound insulation and trim piece, taking care not to damage the seat belt.
http://www.norcalevo.net/gallery/albums/album75/113s.jpg (http://www.norcalevo.net/gallery/albums/album74/113_G.jpg)
Before enlarging the hole even further (to allow the washer and ground wire anchor to fit through), I again re-placed the trim piece and made sure the hole was correctly centered to allow the bolt to go through.
http://www.norcalevo.net/gallery/albums/album75/114s.jpg (http://www.norcalevo.net/gallery/albums/album74/114_G.jpg)
With the holes done, I threaded the control wire (leading from the retractor) through before reinstalling the trim piece, making sure I could find the connector at the end of the wire in the trunk.
http://www.norcalevo.net/gallery/albums/album75/115s.jpg (http://www.norcalevo.net/gallery/albums/album74/115_G.jpg)
I found that bolting the retractor directly wouldn't leave enough clearance for the C-pillar cover, so I used the J-shaped bracket included in the kit; the long bolt replaces the factory bolt, the short bolt attaches to the rectractor. I discovered it was much easier to install the long bolt before bolting the rectractor to the bracket. Also, I used spacers and washers so that the bracket wouldn't totally press in on the trim piece.
http://www.norcalevo.net/gallery/albums/album75/116s.jpg (http://www.norcalevo.net/gallery/albums/album74/116_G.jpg)
Notice the ground wire anchor which goes between the bottom spring washer and the frame. While putting the bolt in place, keeping the ground wire taut allowed me to use the ground wire anchor to prevent the spacer and washers from sliding off the bolt.
Finally, I bolted the rectractor to the bracket, and put the included plastic covers on to the bolt heads to pretty things up. Rectractor installation done!
http://www.norcalevo.net/gallery/albums/album75/117s.jpg (http://www.norcalevo.net/gallery/albums/album74/117_G.jpg)
Sensor Installation
The sensor needs to be attached in a very level orientation, on a fairly solid immoveable part of the car. Installation requires drilling so obviously the sensor cannot be installed against an outside panel, and should not be installed on any structurally critical part that would be weakened by drilling (struts, braces, etc. I looked around and decided the best place was the cubbyhole in the rear left (not too far behind where the fuel door is), opposite the the windshield washer fluid reservoir.
Drilling required that I remove (or as it turned out, bend back) the lining in the trunk. This was easily done by removing the handful of rather small plastic anchors holding the lining in place. For these anchors, I discovered the best technique for removal was to reach to the other side of the anchor and pull the center pin all the way through, thereby releasing the barbs and the anchor.
http://www.norcalevo.net/gallery/albums/album75/121s.jpg (http://www.norcalevo.net/gallery/albums/album74/121_G.jpg)
Below, note the control wire (leading from the rectractor) that I earlier ran into the trunk. I found one hole I could use to attach the sensor, requiring only one hole to be drilled (I used the sensor itself as a template for drilling).
http://www.norcalevo.net/gallery/albums/album75/122s.jpg (http://www.norcalevo.net/gallery/albums/album74/122_G.jpg)
The bottom hole (the one I drilled) is just big enough to fit the bolt, whereas the exising hole is big enough that the nut would pass through it were it not for the washer between them. I actually did this on purpose, because it allowed me to wiggle and tilt the sensor forward/backward enough to make it nicely level, before tightening the nuts (circled). I was careful not to over-tighten the nuts, for fear that it would crack the plastic sensor housing.
http://www.norcalevo.net/gallery/albums/album75/123s.jpg (http://www.norcalevo.net/gallery/albums/album74/123_G.jpg)
Wiring
With the AutoControl system, there is a power wire that runs from a +12VDC power source to the sensor (which is essentially a switch), and a control wire that runs from the sensor to the retractor (and the retractor has a ground wire that I bolted on to the frame). Any interruption of current to the rectractor (notably by the sensor) and the retractor locks the tail strap. This also allows the possibility of adding a "manual" switch on the power wire that, when opened, would keep the belt locked--though I elected to leave this for a later date. However, in anticipation of doing so, I routed the power wire all the way up to the front.
To do so I removed the left front and rear scuff plates; the rear plate has plastic anchors (in the approximate circled positions) and the front has four. I removed both by grasping firmly and pulling until the anchors released. Also, I removed the "cowl side trim" (as the service manual calls it; indicated by an arrow below) to tap the power wire that I needed.
http://www.norcalevo.net/gallery/albums/album75/118s.jpg (http://www.norcalevo.net/gallery/albums/album74/118_G.jpg)
http://www.norcalevo.net/gallery/albums/album75/119s.jpg (http://www.norcalevo.net/gallery/albums/album74/119_G.jpg)
I connected the power wire to the sensor, threaded the wire through a hole where I found several wires already running and ran it next to a couple of thick lines (possibly the trunk release and/or fuel door release lines).
http://www.norcalevo.net/gallery/albums/album75/126s.jpg (http://www.norcalevo.net/gallery/albums/album74/126_G.jpg)
http://www.norcalevo.net/gallery/albums/album75/128s.jpg (http://www.norcalevo.net/gallery/albums/album74/128_G.jpg)
To run the wire from under the rear scuff plate, to under the front scuff plate, I did not need to remove the lower B-pillar cover. Instead, I used a tool I fashioned from an undone wire coat hanger with a loop bent at the end of it.
http://www.norcalevo.net/gallery/albums/album75/127s.jpg (http://www.norcalevo.net/gallery/albums/album74/127_G.jpg)
From in front, I poked the tool under the B-pillar cover, then knotted the wire around the loop, and pulled the tool back out to pull the wire through.
http://www.norcalevo.net/gallery/albums/album75/129s.jpg (http://www.norcalevo.net/gallery/albums/album74/129_G.jpg)
Now I had the power wire running all the way to the front; all I needed was a power source. I studied the electrical, circuit and connector diagrams from the service manual, but in vain. In the end I was not able to match up the connector and wire I wanted to tap (in the manual) with an actual wire. So I got out the multimeter and probed for a suitable wire to splice.
The instructions say to tap a power source that is on only when the ignition is on, so that's what I looked for. Eventually I decided on the yellow wire shown below. I tested with the multimeter to verify the voltage level and to make sure that the current was on and off exactly when I expected. According to page 90-75 of the Circuit Diagrams section of the service manual, the wire I tapped is power line for the power windows, so this should be fine.
http://www.norcalevo.net/gallery/albums/album75/124s.jpg (http://www.norcalevo.net/gallery/albums/album74/124_G.jpg)
The Schroth kit includes a splicing cable with blue "shackles" on each end that made splicing a breeze--no need to strip insulation from the wire or anything.
http://www.norcalevo.net/gallery/albums/album75/125s.jpg (http://www.norcalevo.net/gallery/albums/album74/125_G.jpg)
After I installed the splicing shackle I made sure that power came out both from the other end of the splicing cable (the end with a fuse on it), and from the connector pin attached to the yellow wire (to make sure the shackle hadn't accidentally cut the yellow wire).
Then I attached the power wire to the splicing cable (via another shackle), turned the key to the "ON" position, and made sure that the retractor unlocked. Success!
http://www.norcalevo.net/gallery/albums/album75/130s.jpg (http://www.norcalevo.net/gallery/albums/album74/130_G.jpg)
Conclusion
Finally I put everything back together, started the car, made sure everything electrical was still working as it should, and took the new harness out for a test drive. Everything worked as it should, with the belt locking up under medium acceleration and braking and cornering. However I'm still wishing for a "manual override" switch to keep the belt fully locked, so I'll probably be installing such a switch soon.
I did make one slight goof-up while installing: my SRS warning is now on. I believe this is because I unplugged some connector or another with the ignition on, while probing for a power wire to tap. Notably, the connector with the wire I tapped is C-127 which also has wires going to the air bag drive circuit (according to the service manual). Clearly the SRS ECU would have been unhappy about me disconnecting this while it was active. I was not able to find any way of resetting the warning so I'll have to take the car in to the dealer to get it taken care of.
Kit Contents
http://www.norcalevo.net/gallery/albums/album75/001s.jpg (http://www.norcalevo.net/gallery/albums/album74/001_G.jpg)
The AutoControl features a powered retractor mechanism (upper-left) that locks the tail strap unless a current is applied to it. The sensor unit (yellow) is basically a motion/tilt-sensitive switch that is open when tilted or when it encounters g-forces (acceleration/braking/turning). For this reason it should be installed with the car on level ground; my garage tilts forward ever so slightly so I rolled the car partway up a ramp to level it. The kit includes a bubble-type level so you can ensure the sensor is correctly installed.
Belt Installation
Obviously the chest/shoulder belts go through the holes in the Recaro seat. Contrary to the instructions, I started in front of the seat, threaded the belt through the right-side hole, then back through the left-side hole, because the buckle mechanism would not fit through the hole. Double-check to make sure the belt isn't backwards; the red button on the buckle should face the front of the car.
The left mounting bolt for the lap belt, which is the normally the bolt that holds the factory belt, hidden by a rubber cover that easily slides off. The bolt does not move with the seat, so slide the seat forward to make reaching the bolt easier. The bolt is tightly torqued but otherwise unscrews fairly easily.
http://www.norcalevo.net/gallery/albums/album75/014s.jpg (http://www.norcalevo.net/gallery/albums/album74/014_G.jpg)
Figure out which way the lap belt needs to be bolted on. To prevent confusion when bolting the anchor, I used a felt marker to designate the side of the anchor point that faces outwards--towards the head of the bolt. Also, I fount it necessary to bend the anchor point slightly for a better fit.
http://www.norcalevo.net/gallery/albums/album75/016s.jpg (http://www.norcalevo.net/gallery/albums/album74/016_G.jpg)
This is the bolt with both the Schroth and factory belt anchors on it, along with the factory spaces and washers. At this point, I double-checked there weren't any twists in the belt.
http://www.norcalevo.net/gallery/albums/album75/017s.jpg (http://www.norcalevo.net/gallery/albums/album74/017_G.jpg)
Before putting the bolt back in, I found it useful to slide the rubber cover forward as much as possible, as doing so with the bolt tightened was much more difficult.
Now for the right-side bolt: unlike the left, it moves with the seat and is very close to the center console. It was much easier to reach--working from behind the seat--after sliding the seat all the way back.
http://www.norcalevo.net/gallery/albums/album75/018s.jpg (http://www.norcalevo.net/gallery/albums/album74/018_G.jpg)
Also, I needed to partly remove the rear part of the center console; I undid these two screws at the bottom of the CD cubbyhole and flipped the console up to reach the anchor bolt.
http://www.norcalevo.net/gallery/albums/album75/020s.jpg (http://www.norcalevo.net/gallery/albums/album74/020_G.jpg)
As with the left anchor, I marked the "outside" face of the right anchor so I would know I had it facing the right way. Here's the bolt with the factory and Schroth anchors on it; again, before attaching the bolt I made sure the belt wasn't twisted.
http://www.norcalevo.net/gallery/albums/album75/021s.jpg (http://www.norcalevo.net/gallery/albums/album74/021_G.jpg)
Retractor/Tail Installation
I attached the retractor using the bolt for the factory shoulder belt for the left-most rear passenger. The first thing I did was remove the rear seat, which facilitates removing the trim and will be needed later to route the wiring. The rear seat comes in two pieces, the lower "bench" and the upper seat back. Reaching under the front of the bench you'll find two plastic pull tabs; pulling on these will release the hooks that are the only thing holding the bench in place. With the bench removed you can see the three bolts that you need to undo to remove the seat back. Presto!
http://www.norcalevo.net/gallery/albums/album75/103s.jpg (http://www.norcalevo.net/gallery/albums/album74/103_G.jpg)
http://www.norcalevo.net/gallery/albums/album75/104s.jpg (http://www.norcalevo.net/gallery/albums/album74/104_G.jpg)
Next, I removed the trim piece behind the back seat. First, I removed the plastic covers from the left and right C-pillars: grasp and pull steadily until the plastic claws release. Then, I undid child-seat anchor bolts:
http://www.norcalevo.net/gallery/albums/album75/105s.jpg (http://www.norcalevo.net/gallery/albums/album74/105_G.jpg)
The speaker grilles hold the trim piece in place as well, so they had to be removed. The plastic anchors holding them in place (three on each grille) are easily accessed through the trunk; I undid them by using pliers to tuck in the "barbs" and push the anchors through.
http://www.norcalevo.net/gallery/albums/album75/106s.jpg (http://www.norcalevo.net/gallery/albums/album74/106_G.jpg)
Next, I undid the five light-blue plastic anchors (one shown below) that directly attach the trim to the frame.
http://www.norcalevo.net/gallery/albums/album75/107s.jpg (http://www.norcalevo.net/gallery/albums/album74/107_G.jpg)
A photo of the trim piece removed gives a better view of the position of the anchors:
http://www.norcalevo.net/gallery/albums/album75/108s.jpg (http://www.norcalevo.net/gallery/albums/album74/108_G.jpg)
For these anchors, I used a screwdriver with a small socket head attached which I would push up against the anchor; the socket would tuck in the barbs holding the anchors in place.
http://www.norcalevo.net/gallery/albums/album75/109s.jpg (http://www.norcalevo.net/gallery/albums/album74/109_G.jpg)
The last thing holding the trim piece in place was the third brake light, which I easily removed by unscrewing two bolts (accessed from the trunk) and disconnecting the light from its harness.
http://www.norcalevo.net/gallery/albums/album75/110s.jpg (http://www.norcalevo.net/gallery/albums/album74/110_G.jpg)
The trim piece should now come off. Peeling back the rubbery sound insulation reveals the belt anchor bolt we're after.
http://www.norcalevo.net/gallery/albums/album75/111s.jpg (http://www.norcalevo.net/gallery/albums/album74/111_G.jpg)
I now needed to put a hole in the trim cover so that I could poke a new, longer bolt through. To figure out where on the trim piece to drill, I removed the factory bolt, temporarily put the insulation and trim piece back in place, and used a long thin drill bit through the bolt-hole (again, accessed from the trunk) to poke a small guide hole through the sound insulation and trim piece (which is made of wooden pressboard).
http://www.norcalevo.net/gallery/albums/album75/112s.jpg (http://www.norcalevo.net/gallery/albums/album74/112_G.jpg)
Using the guide hole, I cut larger holes in the sound insulation and trim piece, taking care not to damage the seat belt.
http://www.norcalevo.net/gallery/albums/album75/113s.jpg (http://www.norcalevo.net/gallery/albums/album74/113_G.jpg)
Before enlarging the hole even further (to allow the washer and ground wire anchor to fit through), I again re-placed the trim piece and made sure the hole was correctly centered to allow the bolt to go through.
http://www.norcalevo.net/gallery/albums/album75/114s.jpg (http://www.norcalevo.net/gallery/albums/album74/114_G.jpg)
With the holes done, I threaded the control wire (leading from the retractor) through before reinstalling the trim piece, making sure I could find the connector at the end of the wire in the trunk.
http://www.norcalevo.net/gallery/albums/album75/115s.jpg (http://www.norcalevo.net/gallery/albums/album74/115_G.jpg)
I found that bolting the retractor directly wouldn't leave enough clearance for the C-pillar cover, so I used the J-shaped bracket included in the kit; the long bolt replaces the factory bolt, the short bolt attaches to the rectractor. I discovered it was much easier to install the long bolt before bolting the rectractor to the bracket. Also, I used spacers and washers so that the bracket wouldn't totally press in on the trim piece.
http://www.norcalevo.net/gallery/albums/album75/116s.jpg (http://www.norcalevo.net/gallery/albums/album74/116_G.jpg)
Notice the ground wire anchor which goes between the bottom spring washer and the frame. While putting the bolt in place, keeping the ground wire taut allowed me to use the ground wire anchor to prevent the spacer and washers from sliding off the bolt.
Finally, I bolted the rectractor to the bracket, and put the included plastic covers on to the bolt heads to pretty things up. Rectractor installation done!
http://www.norcalevo.net/gallery/albums/album75/117s.jpg (http://www.norcalevo.net/gallery/albums/album74/117_G.jpg)
Sensor Installation
The sensor needs to be attached in a very level orientation, on a fairly solid immoveable part of the car. Installation requires drilling so obviously the sensor cannot be installed against an outside panel, and should not be installed on any structurally critical part that would be weakened by drilling (struts, braces, etc. I looked around and decided the best place was the cubbyhole in the rear left (not too far behind where the fuel door is), opposite the the windshield washer fluid reservoir.
Drilling required that I remove (or as it turned out, bend back) the lining in the trunk. This was easily done by removing the handful of rather small plastic anchors holding the lining in place. For these anchors, I discovered the best technique for removal was to reach to the other side of the anchor and pull the center pin all the way through, thereby releasing the barbs and the anchor.
http://www.norcalevo.net/gallery/albums/album75/121s.jpg (http://www.norcalevo.net/gallery/albums/album74/121_G.jpg)
Below, note the control wire (leading from the rectractor) that I earlier ran into the trunk. I found one hole I could use to attach the sensor, requiring only one hole to be drilled (I used the sensor itself as a template for drilling).
http://www.norcalevo.net/gallery/albums/album75/122s.jpg (http://www.norcalevo.net/gallery/albums/album74/122_G.jpg)
The bottom hole (the one I drilled) is just big enough to fit the bolt, whereas the exising hole is big enough that the nut would pass through it were it not for the washer between them. I actually did this on purpose, because it allowed me to wiggle and tilt the sensor forward/backward enough to make it nicely level, before tightening the nuts (circled). I was careful not to over-tighten the nuts, for fear that it would crack the plastic sensor housing.
http://www.norcalevo.net/gallery/albums/album75/123s.jpg (http://www.norcalevo.net/gallery/albums/album74/123_G.jpg)
Wiring
With the AutoControl system, there is a power wire that runs from a +12VDC power source to the sensor (which is essentially a switch), and a control wire that runs from the sensor to the retractor (and the retractor has a ground wire that I bolted on to the frame). Any interruption of current to the rectractor (notably by the sensor) and the retractor locks the tail strap. This also allows the possibility of adding a "manual" switch on the power wire that, when opened, would keep the belt locked--though I elected to leave this for a later date. However, in anticipation of doing so, I routed the power wire all the way up to the front.
To do so I removed the left front and rear scuff plates; the rear plate has plastic anchors (in the approximate circled positions) and the front has four. I removed both by grasping firmly and pulling until the anchors released. Also, I removed the "cowl side trim" (as the service manual calls it; indicated by an arrow below) to tap the power wire that I needed.
http://www.norcalevo.net/gallery/albums/album75/118s.jpg (http://www.norcalevo.net/gallery/albums/album74/118_G.jpg)
http://www.norcalevo.net/gallery/albums/album75/119s.jpg (http://www.norcalevo.net/gallery/albums/album74/119_G.jpg)
I connected the power wire to the sensor, threaded the wire through a hole where I found several wires already running and ran it next to a couple of thick lines (possibly the trunk release and/or fuel door release lines).
http://www.norcalevo.net/gallery/albums/album75/126s.jpg (http://www.norcalevo.net/gallery/albums/album74/126_G.jpg)
http://www.norcalevo.net/gallery/albums/album75/128s.jpg (http://www.norcalevo.net/gallery/albums/album74/128_G.jpg)
To run the wire from under the rear scuff plate, to under the front scuff plate, I did not need to remove the lower B-pillar cover. Instead, I used a tool I fashioned from an undone wire coat hanger with a loop bent at the end of it.
http://www.norcalevo.net/gallery/albums/album75/127s.jpg (http://www.norcalevo.net/gallery/albums/album74/127_G.jpg)
From in front, I poked the tool under the B-pillar cover, then knotted the wire around the loop, and pulled the tool back out to pull the wire through.
http://www.norcalevo.net/gallery/albums/album75/129s.jpg (http://www.norcalevo.net/gallery/albums/album74/129_G.jpg)
Now I had the power wire running all the way to the front; all I needed was a power source. I studied the electrical, circuit and connector diagrams from the service manual, but in vain. In the end I was not able to match up the connector and wire I wanted to tap (in the manual) with an actual wire. So I got out the multimeter and probed for a suitable wire to splice.
The instructions say to tap a power source that is on only when the ignition is on, so that's what I looked for. Eventually I decided on the yellow wire shown below. I tested with the multimeter to verify the voltage level and to make sure that the current was on and off exactly when I expected. According to page 90-75 of the Circuit Diagrams section of the service manual, the wire I tapped is power line for the power windows, so this should be fine.
http://www.norcalevo.net/gallery/albums/album75/124s.jpg (http://www.norcalevo.net/gallery/albums/album74/124_G.jpg)
The Schroth kit includes a splicing cable with blue "shackles" on each end that made splicing a breeze--no need to strip insulation from the wire or anything.
http://www.norcalevo.net/gallery/albums/album75/125s.jpg (http://www.norcalevo.net/gallery/albums/album74/125_G.jpg)
After I installed the splicing shackle I made sure that power came out both from the other end of the splicing cable (the end with a fuse on it), and from the connector pin attached to the yellow wire (to make sure the shackle hadn't accidentally cut the yellow wire).
Then I attached the power wire to the splicing cable (via another shackle), turned the key to the "ON" position, and made sure that the retractor unlocked. Success!
http://www.norcalevo.net/gallery/albums/album75/130s.jpg (http://www.norcalevo.net/gallery/albums/album74/130_G.jpg)
Conclusion
Finally I put everything back together, started the car, made sure everything electrical was still working as it should, and took the new harness out for a test drive. Everything worked as it should, with the belt locking up under medium acceleration and braking and cornering. However I'm still wishing for a "manual override" switch to keep the belt fully locked, so I'll probably be installing such a switch soon.
I did make one slight goof-up while installing: my SRS warning is now on. I believe this is because I unplugged some connector or another with the ignition on, while probing for a power wire to tap. Notably, the connector with the wire I tapped is C-127 which also has wires going to the air bag drive circuit (according to the service manual). Clearly the SRS ECU would have been unhappy about me disconnecting this while it was active. I was not able to find any way of resetting the warning so I'll have to take the car in to the dealer to get it taken care of.