I have an 89 with the automatic shoulder belt restraint system. I am going to convert it to a regular belt style from a 91 parts car.

Under the drivers seat in addition to the the two electric connectors for the heated seats there is a two pronged connector. I am assuming this is for the auto seat belts.

Question: By removing the auto belt system will the lack of connective signal interfere with the car running? Will the ECM prevent the car from operating without the seat belt system as installed?

 

That connector on my car activates the seat belt warning light, it might do both things on yours.

 

Had no issues when I removed mine and converted it to manual belts. That no start without the seat belts buckled was a Federal mandate in the early 70s

 

I would like to convert my sealbelts in my 1989 XJS too. Keeps us updated if possible.
Thanks
Joe

 

Joe,
I am well into my conversion.
First thing you need to do is locate a suitable parts car or parts supplier such as Jag Dismantler Noem in TX as one example. I found a '91 about an jour from me in good shape that matched my interior leather color. This is important because you need to change out the rear seat scuttle as the panel is different. The good news is that any year prior to 89 or subsequent thru 91 will work. Your 89 belts are probably black. Prior year car belts are black, by 91 they were color matched to the interior of the car. I like the color matched ones better so I am swapping out. My new belts unfortunately were appealing to some mice at one point so i am sending them off to be replaced by Global Belt in Edmond OK. The rear belts were fine so no need to send them off.

Replacement parts you will need:
'A' pillar covers, L\R
Long thin trim covers that go over the windows. This trim material will match the sail panels at the rear. Four connection points. Need the connection push pins and the rubber grommets they go into on the body
'B' pillar covers with coat hook (most seem to be a neutral sandal color)
Rear seat scuttles with chrome trim opening for belt to go thru
Belt assemblies with mounting bolts. Plastic bolt head covers for upper anchor bolt the goes thru B pillar cover
Floor mounted black belt slide anchor bar with mounting bolt and black plastic bolt head covers. This mounting bolt is longer than the plug bolt they used to fill the hole in 89.
'A' pillar plastic trim between dash and door. 1 or 2 black screws to undo it. (Apparently this piece is a different length on the '89's) (Fragile black plastic)
Seat rails with adjustment bar (Recommended) The 89s have the belt retractors mounted to the seat rail frame. It is not needed with the conversion.

Parts removal:
Remove front and rear seats. Highly recommended. Makes accessing everything go so much easier.
Belt track covers (long 'L' shaped pieces, weird plastic-rubbery material)
'B' pillar covers (look for two screws on the top)
Rear seat scuttle. One screw on back. 2-3 screws on front side, may be covered by material. Just pull it back to locate them. Pry off 3 black clips.
Belt anchor bolts. Will be tight but with force will come free with socket and wrench.
Two 'star' head bolts on B pillar that hold track lock mechanism (one of mine would not come free even with an impact driver)
Remove the phillips screws along the top of window rail. Track mechanism will now be free. It actually is two pieces.
Unplug electronic connections both sides
With electric drill drill out rivets of black plastic trim along top of door and A pillar
With a larger drill bit drill out rivets holding track retaining nut holders
Remove A pillar plastic trim between dash and door opening. 1 or 2 small phillips screws each side then jiggle the part until you get it free. They are fragile.
(The entire system was very much a 'Frankenstine" bolt together arrangement so they didn't have to redesign the whole car)

To install the floor mounted steel anchor bar you will need to cut two holes in the carpet on each side.
First pull the carpet and matting back to find both the anchor bolt hole and the hole with rubber grommet the bar fits into under the rear seat.
Once you locate these holes line them up with the carpet and use a sharp punch to mark the carpet hole location. You can try to cut a round hole for each or make a small 'X' cut in the carpet for the bar and the bolt to fit thru.

If you want to change out the rear belts to another color:
Pry off plastic cover on seat belts for access to bolt, rear side.
Remove bolt from anchor point under seat. Swap belts from another car or send out for new color webbing

Install new belts:
Install replacement A pillar plastic trim
Install A pillar trim
Secure belts to bottom anchor points
Route belt thru scuttle
Secure top anchor point, put cover on bolt head
Secure B pillar cover, attach coat hook.
Route belt down the slide bar, feed loop thru bar, secure slide bar with anchor bolt. then install cover on bolt head
Secure scuttle cover with screws and pinch clips. Don't forget to reattach speaker wires first
Install trim cover above door frame

Install rear belts reverse of disassembly
Reinstall rear seats back with clip hooks and lower screws. Install seat bottom and secure lower locking points.

Swap out front seat frames
Connect belt sensor wiring and heated seats
Secure front seats to mounting posts with star bolts


I am right in the middle of this project so PM me for more detail if needed or for pictures

 

Thanks, Brad, for providing all the detailed information! I’ll start by looking for the interior parts and trim.

 

UPDATE:
There is a black plastic trim piece that fits along the top of the door window and down the A pillar. Drill out the retaining rivets and remove.
You now have access to the track securing nuts held in place with a retaining bracket secured by two rivets. The three across the top have two rivets. The two on each A pillar
have three rivets. Not sure yet if I need to remove the A pillar ones.

With the seats out it is a good opportunity to replace the original material covering the seat rail mounting pedestals. I got an exact color match for my car at the fabric department at Michaels.

 

Getting out the nut retaining brackets was a pain. I had to get a titanium drill bit to work on the rivets after punching out the backsides with a hammer and punch. Persistence paid off.

I did not even attempt to get the third rivet off the two A pillar brackets. I pushed the nut out, flattened the arm with a flat head screw drivers and used a dremal cutting wheel to cut off the arm to the third rivet. Messing around with that rivet that close to the windshield screamed DANGER.

All the automatic shoulder belt hardware and trim is now off the car.

NOTE: You will need four (4) rubber socket retainers, part number BD 47802 and up to eight of the Buttons, pronged, part # BD 13102. These are for the trim panel that goes above the door opening from the A pillar to the rear sail panel. The auto belt cars only have two of the four required socket retainers and used a different window trim piece.

Once I get the belts back from being re-webbed I will be ready to put everything back together. It won't take an hour.