Passenger window not working

[shonwood]

On my '82 928S my passenger window is not working. I have 11.7 volts at the connector ( red/brown). Is there any way I can jumper it out to test it or is the window motor itself bad. Driver-side works fine so it can't be a fuse or relay i'm assuming since they share the same one.

Any suggestions?

Thanks

[Danglerb]

Measured how under what conditions?

What the battery measure?

Assuming you just put a digital meter on it, and the battery is something in the normal range around 12.5v you have a weak connection between that point and the battery. Check fuses etc. and ground points.

[shonwood]

I just turned the ignition where the radio comes on...it measured between 11.7 to 12.1 v. This should be enough for it to do something...you think?

[honerboys]

i'd suspect the switch is bad

[shonwood]

if the switch is possibly bad, how can you test it? the other two grey wire has to be a NO and NC correct?

[garylewa]

Jumper motor first using a 12VDC supply if it works (motor moves window up/down; obviously) the problem is probably in the switch. It's a rocker switch; I wouldn't waste time trying to rebuild these; just purchase a new one.

What dangler stated above is also true; if the motor works off your 12VDC supply but won't work off of the cars voltage do what he is saying

[Danglerb]

Originally Posted by shonwood

I just turned the ignition where the radio comes on...it measured between 11.7 to 12.1 v. This should be enough for it to do something...you think?

The catch is a typical meter measures voltage with no load.

A digital meter often has like a million ohms of resistance on the input exactly so it doesn't place a load on a circuit that may be made of other devices with high impedance and low current capacity. A cars electrical system is the opposite in most cases like your window motor it needs AMPS of current to work.

Lets take an guess that it uses 6 amps to run normally, this means it has something like a 2 ohm internal resistance.

Now imagine what happens if you have a dirty connection with say 600 ohms of resistance, the voltage the motor "sees" is 12v x (2/(600+2)) = nothing.

Measured with the meter though you get, 12v x (1000000/(1000000+600)) and that is pretty much 12v.

[shonwood]

So other than having a separate 12v power supply, there's no way to bypass the window switch?

[924CarreraGTP]

The window switch plugs into a two prong plug behind the console side skirt. You could possibly jump the switch terminals there. If it works, replace the window switch with a good used one (I have one). Though I think you will find it will turn out to be the motor. A lot of window motors go out on that side. I'm not sure why. Possibly different amounts of stress on that side compared to the other. The switches are troublesome though too. Sometimes they can be fixed.

[shonwood]

I pulled the panel apart and it seems to be a bad regulator (motor). When I push the button I hear a slight click coming from the motor. So it appears it may be bad. They seem fairly easy to replace (2 wires and 2 screws) that hold it in place. I'll order one and see what happens.

Thanks for all the helpful troubleshooting tips! This is a great sight for help.

[Mrmerlin]

ahh you can remove the motor and take it apart,and clean it
and then it will probably work they get gummed up.
also lube the pivot on the window arm this gets sticky then overloads the motor this then overloads the window switch

[Danglerb]

One of these?
R Window Motor 78-83, 8 teeth 928 624 014 04 $295.00

I would test it directly with 12v and/or clean it first.

[garylewa]

You can't be 100% sure the motor is dead until you put at least 12VDC to it. Are you sure you are getting the proper output voltage to this motor???
Sometimes DC as well AC motors "hum" until they hit pull-in voltages. Check to make sure you have 12VDC at the motor.

[JGoatley]

I agree with merlin. I had the same issue 2 weeks ago. Took the motor apart and cleaned all the grease off the brushes and coil. Works like new now.

[Dean_Fuller]

You can swap the switch to the other door and see if it works.

[shonwood]

yup...I pulled the window motor and it's dead. I even hooked it up to the battery directly. Now when I I buy a new one, it's remembering where all the screw go. LOL

Thanks for the insight guys!

[Danglerb]

Its good to take pictures as you remove stuff and use a marker and zip lock bags.

[924CarreraGTP]

As someone said above it might be frozen and you can disassemble it to try to fix it. I can sell you a used one if you want. Send me a pm if you're interested.

[shonwood]

Originally Posted by 924CarreraGTP

As someone said above it might be frozen and you can disassemble it to try to fix it. I can sell you a used one if you want. Send me a pm if you're interested.

I took it apart GTP and all f the mechanical parts were free but when I put 12v to it, nothing happened. I think I may have found one locally.
Thanks!

[dcrasta]

Originally Posted by JGoatley

I agree with merlin. I had the same issue 2 weeks ago. Took the motor apart and cleaned all the grease off the brushes and coil. Works like new now.

This:

I had a motor that would stop, and I would 'fonzie' it up (hit the door). Sprayed some Deoxit in the brushes and it works great. Also check for corrosion on the connector to the motor (may want to do that first) . Corrosion increases resistance in the circuit, and causes voltage drops.