W123 300D Window won't open
 

Today, when I drove car in morning, the windows were all working. Car sat in sun for a while. When I got in to come back, I found that the driver side window would not open (no sounds or other indication that it was getting power)

First thought was a fuse had blown. But I seem to recall that driver front and passenger rear are on same fuse. But it is just the one window that is dead.

I suppose motor could have burned out or perhaps console switch has failed or somehow become disconnected.

Any other ideas before I start taking things apart??

More likely, it's a faulty switch. You can test it by moving the connector for the driver side front to the driver side rear part of the switch. See if the window will roll up and down. If it will, it's the switch.

I had one of my Front Windows stop working and was due to the 2 Screws that held the Motor Wires to the Terminal Block being loose. You can see them if you are careful to pry the lowest front part of the Door Panel away from the Door.

There is a couple of thread on removing the Counsel and the Switches and taking the Swich apart and cleaning the burned contacts.

don't lose the 2 Ball Bearings or 2 Springs inside of the Switch.

When it happened to me I used a small Pocket Knife to scrap the burned part off of the contacts.
Also sometimes the Switch is just full of gunk. However, I found Brake Cleaner makes the Plastic sticky so I would not use that.

If not the 2 items above next is a tie between the Motor Brushes being worn out or a Wire where the Door Hinges being broken.

Thanks for input. I will start with switches because I had console out to install radio and perhaps one plug was not fully seated. Then will go to door and check if motor gets any voltage.

My plan for 300D was to touch up wheel wells, but I guess that will have to wait :(

OK, I checked the switches and there is no problem there.

Removed door panel and found power at terminal screws and at motor. So, no doubt motor is toast.

I have had all this out in past, but forgot how to do it. I tried just removing motor (two Torx 20 screws), but that just removes the cover. Motor armature won't come out.

So I guess I have to remove the complete regulator. Is there any more to it than removing the three bolts? Window is in up position.

Power does not a complete circuit make. You need to check the ground portion of the circuit before you jump to conclusions about the motor.

Power to motor is a two wire circuit. Not grounded through chassis. If there is 12v at motor terminals and it doesn't run, then it seems to me motor is bad.

I found section in manual on removing regulator, but because windows is in 100% up position, it seems I have a problem getting at bolts on lift rail. (its coming back to me now, how I installed the regulator last time.

Maybe if I undo the regulator bolts it will drop enough to get at them? Anyway, will try that after lunch.

In order for the motor to run, it needs power at one terminal and continuity to ground at the other. With the switch not actuated, the motor normally has power at both terminals. Actuating the switch completes the ground path for one motor terminal; it would be a good idea to verify that is happening before you condemn the motor.

Take a look at your battery ground strap and tell me if it connects to anything but the chassis. In the final analysis, everything is grounded through the chassis.

That would be a faulty assumption. The motor will not run with 12v at both terminals.

querty, I do know how to troubleshoot electrical systems and have done so. I said I had 12v at the motor terminals and the motor wouldn't run - where do you get me saying 12v at both terminals?? Give it up. I don't have an electrical wiring problem or a bad ground.

The motor IS bad. I will post some pictures of why it will not run later. May be useful to others who go out and buy new regulators.

You should have 12v at both terminals. Do you? Or don't you?

I have sort of followed this and the way you are saying things is not entirely clear.

I think what you are trying to say is that if one of the Meter Probes is grounded no matter which direction on the Switch is applied your are going to show 12 Volts at Both Terminals if the Motor Wires are still connected to the Terminals.
Because the Voltage should go from the Wire through the Motor and back out through the other Wire and through the Meter to the Meter Probe that is grounded.

If someone was doing the above test and got zero Volts on one terminal you would expect and open circuit some where.

Another test that could have been done and may be the easiest to see if the Motor is getting Voltage and the Switch is grounded is to remove the Motor Wires from the Terminal.

Put on Probe of the Volt Meter on one Terminal and one probe on the other. Have some one press the Window Switch and Voltage should show up It may show up as + or negativ Volts. When someone presses the opposite side of the Switch Voltage should show up again but this time the polarity will be the opposite of the first reading.

Before I would have condemned the Motor I would have disconnected the Motor Wires and connected them to a Battery with Jumper Wires to see if the Motor would run.

With the window switch in the neutral position, both wires to the motor supply battery voltage to the motor. (Neutral means that neither the "UP" or "DOWN" position has been selected. Both means two wires out of a possible two.)

Do you agree with that? Or do you disagree?

Just to conclude.

I first removed the bad motor. Some pics below showing commutator covered in grease. Lip seal as shown in one pic was worn and probably let lube through into motor.

Removed entire regulator, installed spare motor and everything is good. (except I need to go back out and put the door covering back on and clean sticky tape residue off the window ;)

BTW, assembled old motor on spare regulator and even although cleaned up, it still won't run. Haven't checked but could be bad connection one of brushes because armature checked out OK. (I have another 3 so not spending any more time on that!)

BTW2, In testing motor, I hooked meter up to motor terminals. Operated window switch and got +12v or -12V depending on switch direction. Don't know what kwerty was on about, but if motor doesn't run when 12v is applied, the motor is bad. (PS I did check it with 12v lawn tractor battery too)

I am not sure on that. I did not probe the Terminals Block with the Switch in the Neutral Position.
I don't know if I am curious enough be pulling my Door panel just to see if that is correct or not; my Wife has the Car at work.

It would be easy for the OP to check that.