Kevin in Atlanta

Will they work? My initial testing suggests not. I connected the red, brown and black and got nothing to move. Verified power, etc.

Mrmerlin

the memory computer is bolted to one of the seats
IIRC it is the passenger seat if you remove it and re solder the board you may get it working again.
you may also need the memory selector thats on the driver side armrest,
NOTE this also controls the mirror memory

Kevin in Atlanta

So, the short answer is no. I am going to return at least the DS - the PS seat has no memory.

Mrmerlin

the memory computer is made to control both seats and mirrors,
there is only one computer /relay board,
if you have a matched pair of seats the computer will run them both,
but the correct wiring must also be available,

I think that the computer can be removed and swapping a few pins will let the seat operate without memory ,
maybe Alan will chime in here to advise on the correct wire layout

Vilhuer

AFAIK if car has M538 passenger side memory seat option its totally separate relay board under the passenger side seat and has nothing to do with drivers side. At least ones I have seen have had separate parts. It used exact same board but each seat needs its own.

Kevin in Atlanta

Well the PS has no memory - DS does - Unless there is a 'simple' way to get around the memory, I would prefer to return them. Memory seats are more expensive.

Alan

If you have dual memory seats then each seat is unique and has its own relay & memory unit under it. For memory to work you need a memory seat and mirror/seat memory switch pad and the wiring to it from the seat.

There is only one mirror memory set up (drivers side) for both mirrors. the passenger side has its own seat memory switch pad (you need that too in pass. config), this connects directly to the Pass seat only.

The mirror memory units shares the switch pad on the drivers side - thats all - it only drives the mirrors, you don't need it for seat memory, but you do need the switch pad.

Cars built in years that had memory seats available are usually wired for it (on both sides) you can check for evidence of this.

It should work - you can even test the seats out of the car.

All you should need is:

30 (+12v constant 30A fuse) to Pin "Term30" on the under-seat controller T20/21 (L/R) Pin 2
31 (Ground) to Pin "Term31" on the under-seat controller T20/21 (L/R) Pin 1
15 (Ignition +12 15A fuse) To Pin "Term15" on the under-seat controller T20/21 (L/R) Pin 4

I believe the manual operating mode from the switches should work even with the memory disconnected.

There are fuses for the seats and seat heaters make sure they are installed correctly.

Alan

Mrmerlin

Thanks Alan for adding the correct info,

Kevin in Atlanta

Interesting - I tested from the harness in the car to the seats outside the car and there was no action. I verified power at the harness and to the seat using a test light.

Alan

Do you know that they were functional in whatever they came from?

I'd suggest you try again and try all directions? I see no other reason they shouldn't work.

Alan

Kevin in Atlanta

I ***-ume they worked :-). I will try again tomorrow.

The red and brown wires were apparent - the third wire at the seat harness I assumed was black. The seat is missing the black plastic clip so I am left to guess a bit. And thanks for your help!

Dave928S

I can confirm that you can run the seats out of the car, as Alan suggested, and that the seat drive buttons all work. I had a totally fried memory board and everything worked fine.

Without delving into the electronics, it seems to me that the memory board acts as an override (supplementary to normal function) that returns all motors to a specific drive position, which is determined by a pot on the drive cable head of each motor. The non memory seats are identical to the memory seats, but don't have the memory pot on each drive head, and also don't have the memory board to hook up to those inputs and the motors as an output. Trigger the memory and it drives the motors until they reach the remembered pot positions.

Kevin in Atlanta

My wires at the seat connector are a jumble - does anybody know the wire color at the seat connector I need to run in addition to the ground and red?

Shane

I've had the same problem putting memory seats into Helmut that came out of an '89. I'll go get some pics of which wires I used to get the memory DS seat to work minus the memory function.

Kevin in Atlanta

That would be great.