1990 300te windows inoperative

The only way the windows and sunroof work is if someone holds the key in the rear hatch lock all the way to the left. Unless this is done, nothing moves. In addition, if the car is unlocked from the driver's door, the alarm goes off and only stops if the key is inserted in the rear hatch lock or the passengers door lock. I would appreciate any suggestions.

looks like more than one problem, as far as the windows are concerned perform the smell test to the convenience control unit under the left rear seat. All the window switches and your door lock switches go to this control unit and then the control unit provides the output to the window motors. Of course check the fuses under the hood, fuses G and H, fuses 9 and 2. You will need a wiring diagram to perform further testing of the switches.

the alarm system is going off due to a couple of reasons, one there are switches in the door lock cylinders and switches that are part of the lock actuators themselves. While in the car you should be able to lock one door and all the others will lock, also if you unlock the door all should unlock do this with the lock knob not the key. It already looks like you have a issue with the door lock cylinder switch on the drivers side or wiring.

Sorry no simple fix.

Dont mean to hijack this thread, but I believe I have the same problem on mey 93 e300. Wife sitting w/ car in park radio and engine on. Puts it in drive and the radio quits working. Gets home and the window will not roll up. I was able to roll the windows up and down with key in driver door.

All fuses are in working order and ohm out fine.

1? Does the radio and windows work from the same circuit?

2? Sounds like this may be the box under the drive seat as mentioned, best place to purchase one from?

3? I assume I have to take driver seat out to replace this box? Whats the easiest way?

4? Link for a wireing diagram. I would rather try to trouble shoot this out rather than just swapping out a box.

I would appreciate any and all help.

Thanks,

i do not have the diagrams in front of me right now but i can check. you may be able to get the diagrams from the library, the one by me has a version of ALL DATA. A big issue with Benz in on the 1993 to 1995 e-class cars, the correct information is harder to find. ( thanks benz ) the box is under the left rear of the rear seat. easy to remove, just push on the release latches at the front/bottom of the seat, one on the left and one on the right.

you are right, testing inputs and outputs are needed before replacing anything and without the diagram you are going to be lost.

the window switches and the door lock switches are connected to the same control unit under the rear seat. if they roll up with the key then the output driver for the control unit is ok. sounds like you might have wiring problems around the shifter, radio wiring and window switch wiring are all in the same general location. you will need to test the wiring.