Electrical seat forward/back and up/down problem

[Cro]

Having a weird one with my passenger side M3 seat (drivers works fine)

Tilt function, lumbar and side bolsters work fine but I checked the fuses anyway just to be sure

Forward and backwards and up/down has stopped working, can't see any loose or cut wires when I tilted the seat up to get a look underneath

When pressing the switch to move the seat forward there is a click inside the black box, nothing happens at the motor. When pressing to get it to go back the motor works slightly, but the seat is already as far back as possible anyway. This is the motor attached to the silver horizontal brace.

If the switch is pressed to lower the seat there is a click inside the black box, if you press to raise it I can feel the motor click. This is the motor at the rear of the underside of the seat you see in the photo




Maybe its coincidence both have gone and its just the motors, or something in the black box? Any ideas what to check out? or how can I test the motors? The motor on the silver rail has connections going into both ends so no idea where I would even attached a +ve and -ve 12v

Drivers works fine

 

[Cartunes]

the Motor will have two really thick wires in comparison with the others. These will be + and -, depending on the direction of travel. If you can get these moving with a fused live and earth supply, that will rule out the motors. It might be corroded or burned connections - check them all physically first.

If you find that the heavy wires aren't showing a +12v out from the black box, then the relay contacts inside it may have failed.

 

[Cro]

Cheers del I'll have a look. From memory I think there were a couple of thick wires on both sides but i'll check with the multimeter

 

[Cro]

the Motor will have two really thick wires in comparison with the others. These will be + and -, depending on the direction of travel. If you can get these moving with a fused live and earth supply, that will rule out the motors. It might be corroded or burned connections - check them all physically first.

If you find that the heavy wires aren't showing a +12v out from the black box, then the relay contacts inside it may have failed.

Motors are grand Del, moved forwards under an external 12v source. Then it works grand moving the seat back again, just that forwards motion. Relays inside something that can be fixed or new box time you think?

 

[Cartunes]

Motors are grand Del, moved forwards under an external 12v source. Then it works grand moving the seat back again, just that forwards motion. Relays inside something that can be fixed or new box time you think?

I've repaired many, by soldering normal relays onto a PCB, but this sometimes takes hours - probably better finding a control box second hand, or at least pricing it.

 

[Cro]

I've repaired many, by soldering normal relays onto a PCB, but this sometimes takes hours - probably better finding a control box second hand, or at least pricing it.

Turned out to be the control box, picked up a cheap one for £20 on eBay matching the exact same numbers and worked once plugged in. Cheers for the suggestions Del

 

[Cartunes]

Turned out to be the control box, picked up a cheap one for £20 on eBay matching the exact same numbers and worked once plugged in. Cheers for the suggestions Del

Yah, it's the most obvious failure mode mate - heavy current erodes the contact every activation, so the relays inside yon box have just given up. Having said that, my repair would have been 50-60 quid, you got off lightly there. I once had to change the relays inside a Rover BCM, took 6 hours to dismantle the dash, remove the unit, replace the relays and put her back together again. The customer was relieved it was only £100....