Hi guys, so I've been struggling with my electric drivers seat since I bought the car. The electrics do not work in any mode, and the seat is stuck in the as far back as it will go position. The driving position is fine for me but the wife can't reach the pedals and thinks i'm deliberately not mending it!! As if!! Anyway I've tried swapping the seat module for the passenger side (as per Jimbob's advice, thanks Jim) but no joy. The drivers module works in the passenger side so it's not that. I've checked all the fuses and they're fine. I've tried un-doing the front mounting bolts to gain further access but still no joy. I can't get to the bolts holding the back of the runners, to take the seat out all together because of the seat position. I'm assuming the wiring has snagged or broken somewhere under the seat. Any ideas how to proceed from here?? Incidentally the seat belt warning light doesn't go out either so I wonder if this wiring is also damaged? Do I have to take the seat apart bit by bit to see if I can gain access to the mounting bolts? Any advice appreciated.

 

Sounds like you've done a lot of debugging already.
In order, here's what I'd try:
While banging and bouncing on the seat, push the buttons. Sometimes there's a little "dead spot" in a motor and some small jounce may get it going again. Cause: lack of use or intermittent wiring.
Since you checked the fuse (more than visually? Are you getting voltage?). You could put an amp meter in the circuit for the passenger seat, move the seat or seatback and note the current. Repeat for Driver's side. If the current is higher - you may have a sticking motor (they draw more current when stalled). If you get no current at all, I'd suspect a poor ground wire on the control module. SD5-2 is the "connector" number for ground. SD5-1 is also grounded to identify the seat as being the driver's. SD5-5 is power going in.
Swapping the control module is a great test of all the inputs and outputs. So I'd be thinking "power or ground" - by the way, it's unlikely that ALL motors would simultaneously get stuck in a dead spot, so if your symptom is ALL motors, lumbar, and seat belt switch failing to operate, etc., I'd be checking power and ground.

Worst case, since you seem to be able to access the control module, wire a jumper of some sort (I'm deliberately not describing the steps) to run the driver's seat motors to a desired position, then you can access the mounting bolts.

(My Jag had a poor connection to the seat control module causing similar symptoms.)

 

My driver seat stuck in the back position after I drove it there during cleaning the car, with no one siting on it. It must be a loose wire, but I can't get to it. 98 xk8 conv.

 

Resurrection. I found the broken 20A fuse, replaced it and the seat moves. Now I have to find out why the fuse gets blown, it happened before I bought the car. In fact both of the 20A fuses were missing from the spare fuse case in the trunk. I found a piece of aluminum candy wrapper under the seat mangled into the motor housings and wires. This may have nothing to do with the issue but who knows. 98 XK8 "topless"

 

I had the same thing happen to me, every time I sat in the chair the fuse would blow. Without anyone in the chair it moved fine.We took the chair out of the car and turned it upside down and virtually disassembled the various wiring looms and plugs until we found the very small chaffed wire causing the problem. Just wound several layers of insulation tape around all the wires and put it back in the car cable tied in a better place. Now all works fine. Cheers
John

 

+1 - there'll more than likely be some worn insulation that's shorting and blowing the fuse. i had the same problem, same cause

 

I had a similar problem that was for the up/down motor. The springy wires that form the suspension to the seat have a long stiff wire tail sticking down. When the seat was at or near the bottom of its travel, one of these seat wires would hit the motor wire, eventually cutting through the insulation, causing a short, and blowing the fuse. Wrapped the damaged wires with electrical tape and bent the seat suspension wire in that area a little and problem was solved.