My drivers seat is no longer moving when trying to use the control panel and I am trying to figure out whether the seat motor is no longer any good or whether the control unit attached to the side of the seat is the culprit. I would appreciate any assistance in troubleshooting this. Additionally is there a method for moving the seat manually in the interim and an easy means of removing the entire seat if and when the time comes that it is necessary?

Dear kirke333,

May this find you well. The problem is almost certainly in the switch assembly or the seat computer: the seat motors rarely fail (sometimes a drive cable is worn to the point where the motor no longer will turn it).

There is no way to move the seat manually, when the motors fail.

The seat switch sometimes ceases to work, because it is filled with dirt/debris. Sometimes, solder joints on the circuit board develop microscopic cracks. These are just enough to keep power from flowing. You can reflow the solder, using a 15-25 watt soldering iron.

Before you do this, do you hear the seat computer's relays operating, when you press the switch buttons? If not, that may be the source of the problem. The seat computer is affixed to the underside of the seat. You should be able to get a replacement from a salvage yard.

The seat can be removed. It is secured by four bolts, one at each end of the seat track. Please read carefully, the following:
DEATH DANGER WARNING: Before trying to remove the seat, remove the negative battery cable clamp from the battery terminal, and put the clamp in a plastic bag, to isolate it. This cuts power supply to the SRS (Airbag) System. The airbag sensor is under the driver's seat, affixed to the floor pan. If this sensor is banged - if you drop the seat on it, or drop a tool on it - the airbag could deploy. This can be lethal, at close quarters. It will also be costly: a new sensor is about $1,200. A new airbag is about the same. You should wait 30 minutes before starting work, after you cut power to the vehicle. Have the radio security code handy: you'll need it to restore the radio to service.

Hope this helps.

Yours faithfully,

Spook

Thank you for the information and I'll start to listen for the seat computer relay. If the computer is the problem, can it be removed without removing the seat?

Also I neglected to mention that the entire switch control unit has broken off of the seat and dangles to the side now. It appears that the plastic has broken at the 2 connection points where it should attach to the seat. Can this piece be modified in some way to reattach or should I be trying to locate another? I was under the impression that the switch itself can be purchased seperate of this.

Thank you again in advance.

Dear kirke333,

May this find you well. It is not feasible to try to remove the seat computer, without removing the seat, unless your hands are far smaller than are mine, and mine are pretty small. There is simply not enough work room under the seat.

The switch mounts to a plastic seatside moulding, which can likely be found at a salvage yard. These mouldings do not interchange between driver's seat and the passenger seat. Any color-compatible item from a 1991-94 940 or 960 will fit. Some from post 1990 740s might also fit.

The switch indeed is separate. Any switch from a 1991-1994 940 or 960 will fit. The passenger side switch - which does not hook-up to a seat computer - has different electrical connectors, and will not serve in place of the driver's side switch.

Hope this helps.

Yours faithfully,

Spook

Thank you again. I guess I'll try to find one of the side seat moldings and a switch and see if this is thew fix I look for.