RRC '92 - Electric seat blocked

RegW · Oct 28, 2018

Hi - my seat controller doesn't work anymore whilst my driver seat is blocked in an uncomfortable position. The wiring is complex and requires a PHD in electronics - 2 garages haven't been able to find the fault so far.
Is there a way to mechanically adjust the seat using a tool - to put it back in the good position (e.g. e.g. using the allen key)? Any other suggestion apart from applying for an Electrical Engineering degree?
It's a 1992 RRC - 3.9i.

pete1987RRC · Oct 28, 2018

Yes ypu can but its slow.
Disconnect the drives at the motor and spin with a drill.

BEt your ecu is toast

Dippypud · Oct 28, 2018

pete1987RRC said:
Bet your ecu is toast

Why it is toast is another matter ... usually water ingress, but anything is possible with green oval stuff ....

RegW · Oct 28, 2018

pete1987RRC said:
Yes ypu can but its slow.
Disconnect the drives at the motor and spin with a drill.

BEt your ecu is toast

Many thx for your swift reply - were you able to do this without taking the whole seat & rails out? It's really hard to reach... or is it easier to replace the ECU (if I can find it somewhere)?

RegW · Oct 28, 2018

RegW said:
Many thx for your swift reply - were you able to do this without taking the whole seat & rails out? It's really hard to reach... or is it easier to replace the ECU (if I can find it somewhere)?

(I found the ECU on Rimmer Bros for £1121.66 - a bargain!)

Ratae · Oct 28, 2018

Either that or the battery on the seat ecu has leaked & damaged the circuit board which is a common issue on the RRC.
http://www.carelect.demon.co.uk/rrseat.html
Pics in this ebay link:
https://www.ebay.co.uk/itm/Power-Seat-ECU-1991-1995-Range-Rover-Classic-PRC-9864-/170857649263
Some stuff on the net where people have dismantled & repaired them with varying degrees of success.
I've seen articles where the ecu has been replaced with relays but I know some disappeared when photobucket did their highway robbery thing & I can't locate any others.
There's a few articles on the AULRO forum (Australian) & some have converted to switches & done away with the ecu but you need to be logged in to see the pics.

I think there may be MOT issues if the driver's seat can't be moved but I stand to be corrected on that.
6.2.5 Driver’s seat
A driver’s seat: fore and aft adjustment mechanism not working as intended. Fail category Major.
https://www.mot-testing.service.gov...dy-Structure-and-Attachments.html#section_6.1

RegW · Oct 28, 2018

pete1987RRC said:
Yes ypu can but its slow.
Disconnect the drives at the motor and spin with a drill.

BEt your ecu is toast

A few minutes ago a swapped the working ECU of the passenger seat with the one of the driver seat. They're different because the memory function isn't there for the passenger - anyway, the seat didn't move with the working ECU either (I was hoping it to work with the memory jack plugged in). So perhaps it's not the ECU?

RegW · Oct 28, 2018

Ratae said:
Either that or the battery on the seat ecu has leaked & damaged the circuit board which is a common issue on the RRC.
http://www.carelect.demon.co.uk/rrseat.html
Pics in this ebay link:
https://www.ebay.co.uk/itm/Power-Seat-ECU-1991-1995-Range-Rover-Classic-PRC-9864-/170857649263
Some stuff on the net where people have dismantled & repaired them with varying degrees of success.
I've seen articles where the ecu has been replaced with relays but I know some disappeared when photobucket did their highway robbery thing & I can't locate any others.
There's a few articles on the AULRO forum (Australian) & some have converted to switches & done away with the ecu but you need to be logged in to see the pics.

I think there may be MOT issues if the driver's seat can't be moved but I stand to be corrected on that.
6.2.5 Driver’s seat
A driver’s seat: fore and aft adjustment mechanism not working as intended. Fail category Major.
https://www.mot-testing.service.gov...dy-Structure-and-Attachments.html#section_6.1

RegW · Oct 28, 2018

Many thx - I think the ECU you're referring to is not the one for the classic model - see the box on
https://rimmerbros.com/Item--i-GRID009405
There's also this solution on eBay;
https://www.ebay.co.uk/itm/Memory-S...h=item5d33639b16:g:p78AAMXQ-KRRhJd3:rk:2:pf:0

RegW · Oct 28, 2018

Does anyone know if you can fit a manual seat on the same rails? I don't need electric controls - might as well swap them out instead of starting to solder diodes etc...

pete1987RRC · Oct 28, 2018

RegW said:
Does anyone know if you can fit a manual seat on the same rails? I don't need electric controls - might as well swap them out instead of starting to solder diodes etc...

Not sure if you can fit a manual seat? May be hard to find in the right trim.
The ecus are very different and you cant swap them over, are your mirror adjusters workimg also as they are also controlled by the ecu.

If you can figure the plugs out you could try a live supply going to the correct motor, this does wprk and i have done it.

Replacement ecu is expensive, rebuild using relays.

pete1987RRC · Oct 28, 2018

Dippypud said:
Why it is toast is another matter ... usually water ingress, but anything is possible with green oval stuff ....

I have 2 toasted ones, i do believe they also get eaten but the battery but mine are all toast!
Toasted at the relays

RegW · Oct 28, 2018

(yes, my mirrors don't adjust anymore either...so it is definitely the ECU that has failed)

Datatek · Oct 29, 2018

RegW said:
(yes, my mirrors don't adjust anymore either...so it is definitely the ECU that has failed)

There is a battery in the ECU, this fails and corrodes all the PCB tracks in the vicinity. It is possible to repair the ECU.

pwood999 · Oct 29, 2018

Diagrams are in the "RAVE ALL Models" version. Here's a PDF of pages 351-419 for the Power & Memory Seats. There's troubleshooting guides in there as well.

The motor wiring looks like it would be fairly easy to convert to non-memory power seats assuming the motors all work.

I would guess replacing with non-power seats should be easy if you get manual seats complete with rails, and use the same body mount points ?

pwood999 · Oct 29, 2018

there's even ebay adverts for ECU repair kits !!

or call these people & get them to repair the ECU. . . . . but check fuses & relays first !!

RegW · Nov 1, 2018

So I opened the ECU and there are no battery leaks.. could it be a fuse ? They all look good (the ones located at the front under the driver's seat - unless you know which one in particular to doulbe check?) Thx!

Datatek · Nov 1, 2018

RegW said:
So I opened the ECU and there are no battery leaks.. could it be a fuse ? They all look good (the ones located at the front under the driver's seat - unless you know which one in particular to doulbe check?) Thx!

Did you check the battery output?

RegW · Nov 4, 2018

Hello, so my existing battery shows 0.5V when unplugged...could that be the cause? I had to break the seal of the case to open it - suggesting that it's the original battery. Its true that my RRC is in fantastic condition overall - extremely well maintained throughout the years.

Datatek · Nov 4, 2018

RegW said:
Hello, so my existing battery shows 0.5V when unplugged...could that be the cause? I had to break the seal of the case to open it - suggesting that it's the original battery. Its true that my RRC is in fantastic condition overall - extremely well maintained throughout the years.

That is a dead battery, you are lucky that is hasn't started leaking and rotted the tracks. It will not work with the battery in that state. From memory it's 3.6 volts.

RRC '92 - Electric seat blocked

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