shandonman
New Member
Please can anyone find me a circuit diagram for the power seats for a 92 ? The manual I have is NAS which doesnt have the memory ecu etc
Ahh...glad I joined the forum, I have the same problem on my 93 not bothered about the memory seats just the mirrors..![]()
I am quite happy to lose the memory function but as you say its a MOT requirement that the drivers seat can be moved back & forth so my next step is to get this ruddy ecu out, open it up & see it its repairable. If not & I am not feeling like spending hundreds of pounds on a replacement I will try and manually wire the seat & mirrors. I am going to study the diagrams when I get a break over the weekend.
I'm pretty sure you have to have a working drivers seat to get an MOT these days so would suggest you look in to it. BTW you can't run a memory seat switch the same as a non-memory seat switch because of the difference in operating voltage/current. It might be possible to use a non-memory switch and re-wire the seat control but then not sure what you'd do with the mirrors?
Dunno if these will help - You can see where the battery is and when it leaks it damages the tracks and also a couple of the chips on the board. The same ECU is found in Rolls Royce/Bentley cars of circa 1989/90 vintage or therabouts. If you trawl the net there are is some information available not I didn't find much to help with making repairs or by-passing the damaged section of the board, after all all you need to to get a switching voltage to the right relay to make things work - I thought "how hard can it be?" - impossible (for me!) appeared to be the answer.
If the polarity is reversed the motor runs the opposite way so it should be viable to build a little switch box directly supplying 12v to the motors.
I think that is viable, I did some continuity testing on that ecu I posted pics of, the relays are the main control for the seat motors, the rest of the board is as far as I can tell given over to a microprocessor driver and memory chips for the mirror and seat memories but I could be wrong, I'm no micro electronics wizz.
If you do a search I have a vague recollection that somebody did make their own switch box.
You are right![]()
Thanks Datatek, nice to know. I don't suppose you would know of a way to hotwire the ECU do you? The reason I ask is I have a damaged ECU which I think I might have made worse by an inexpert attempt to repair a damaged track, the relays are all good but I have no way of knowing if I can get it to work by by-passing a part of the board. I suspect it would be well beyond my ability anyway but always worth asking the question. Cheers.
With the car and the ECU in front of me, it would be perfectly possible, but as I have no info on the wiring etc it cannot be done from here. It would not be a five minute job though.
Different switch current rating I would guess. To bypass the ECU, all you need is to ID the sets of switch wires, should be 3 per switch and the relevant motor wires, 2 per motor, you need 2 relays per motor to give forward and reverse.Whilst I need to find some time to tackle the removal of the ECU, my attention has moved to the passenger seat. All functions work except rearward base so the seat is stuck fully forward. Studying the relatively simple wiring diagram I see the switch uses no ecu, no relays and has a full 12v being applied to the motor through the seat switch.