Hi,

I have a 1987 300SDL, the drivers side power seat is in the all the way to the floor, and all the way back position.
I can't see over the dash board with it like this.

The passenger side seat back works, and the headrest, as well as the up and down, but the fore and aft does not work.

The drivers side is totally dead and does not do anything, the memory feature on the passenger side does not work either.

It appears that the switches and all wiring are properly connected and grounded. If you expose the terminals on the passenger side switch and apply ground to them you can operate the passenger side to the extent that it will work(lacking the fore and aft).
Try this with the drivers side, and still nothing at all.

There is a junction box in the driver footwell under the carpet(not sure if it has anything to do with the seats) there is power there if that info helps.

I know the seats don't work with the doors shut and the car off. The telescoping steering also does not work.
I do have diagrams from a manual I bought on ebay. I am at a loss here, any help would be apprecaited.

Any suggestions?

Thanks!

Teron

 

First thing to do would be to check the fuses, altho they are probably all on the same one. Ck to see if you have power to the motor (with a VOM). If you have power & still nothing, it's a bad motor (unlikely). If you don't have power when you operate the switch, start following it back to the power source.

 

All fuses are good, there is power to and from the fuses, as I said, there is power to the junction box in the driver footwell.
It appears it's getting power yet nothing is working.

Anyone have any ideas? Is this a typical problem?

Teron

 

look.

the switch goes to seat control unit first before the motor.

if the power supply is ok and the switch is okay, and the motor is okay... then what could it be???

[IMG]local://upfiles/1/4B5CAA518AE14C08BFF0DDB2981FE670.jpg[/IMG]

 

My uncle had the problem with a 1990 model and took it to the dealer. The dealer could not fix the problem until a mech disconnected the car battery for about a minute and reconnected it. The seat worked again. Maybe it will fix your problem too.

 

In applying power directly to the motors, they work fine.
Though the back of the seat adjustment only appears to operate when two motors are active at the same time, so that could not be tested. (you're not supposed to cross the beams! Egon was very clear on this matter!)

There is power to the door switch and to the wiring that goes to the seat control unit.

Can I swap the passenger side control unit to the drivers side without any problem?

Teron