Spent the day trying to fix the powered seat adjustment

[V]

My '93 XJ failed its MoT on inoperable driver's seat adjustment. I never adjust it so I didn't notice that the switch gear in both seats had failed.

 

I found that there was no power on the feed to each seat. I checked the factory service manual for a wiring diagram and fuse location and found that the 1993 FSM (updated in 1999) doesn't have a RHD wiring diagram. The fuse panel and numbering is different to the LHD model. Fortunately, I have a 1994 FSM and this had the correct fuse panel diagram, but I had to go through all of the individual circuit diagrams to build up a table of what each fuse supplies. Sadly, RHD powered seats were still not documented by 1994 so I then went to the 1995 FSM and found some of the missing info. The seats are powered from Fuse 1, a 30 amp (green) fuse which was tested OK. It is permanently live. However, the diagrams showing the cable runs, connectors and splices don't show the two feed wires to the seats. They also have a number of differences between what my 1993 has and what is documented for 1995.

 

I left tracing the cable route for a while and rigged up a temporary power feed direct to a spare car battery. I got movement from one switch briefly which was a good sign. I squirted contact cleaner into the switches and gave all the switches a good wiggle and one by one they slowly started to come back to life. I did the same for the other seat and went back to searching for the feed.

 

I am cold, and it's too dark to keep searching without torch light so that's it for today. The diagram I have for a 1995 XJ says that connector C201 is the fuse panel and it is connected to connector C247 in the LEFT kick panel. From there the wiring proceeds to the base of the 'B' pillar where there is a splice S303 that runs to the seat power plug. It doesn't look like there is one. I will have to unbolt the seat belt anchorage as it his holding the carpet down to tightly to feel underneath for a cable. I reckon the the diagram is wrong as the title says 'RHD' but the diagram says 'LEFT seat (driver)'. I have removed the lower trim panels on the left and the left front seat but I reckon the wiring and connectors are all on the right hand side and the RHD diagrams and text are both wrong.

 

The seats are earthed through ground G301 which is in the left rear quarter. That ground is also used for the chime module and it is working. I will take the trim panel off in the cargo area and give the grounding point a clean just in case. I can't tell from the documentation what else uses Fuse 1 if anything. Fuse 1 isn't documented in the panel, I only found it by tracing each component in the wiring diagram.

 

If I run out of time I will just cut the factory plugs off the seat harnesses stuck that come out of the carpet and rewire them to the battery with 30 amp cable and fuses. I will pull Fuse 1 and see what doesn't work.

Edited November 29, 2020 by V

[V]

I couldn't find the broken circuit so I cut the plugs off the seat wires that emerged from the carpet. I reused them on a new fused power feed from the battery. I put in enough cable so I could make changes later on. I think it is time to install an accessory fuse box under the dashboard for everything that I need a non-ignition controlled feed for.

 

Anyone used one of these 40 Amp circuit breakers before?