The Money Pit

Last year I redid the whole interior, and at the time replaced both window motors, and regulators....which worked well for about six months. Been busy with other projects, and hope soon to get going on the Vette again.

My question.

Is there a wiring breakout (connector) under the dash, or kick panel, that would allow me to test the window motor without tearing the door panel off? Hoping to isolate wiring from the motor.
I did check the switch with a voltmeter, and saw a huge drop when activating the switch,.....not looking good for the window motor, but a breakout point would be nice.

FWIW, the passenger window still works perfect.

drwet

In my experience the most likely culprit is the wiring where it passes from the body to the door in the door jamb. Constant flexing with opening and closing the door eventually causes a wire to break.

Big2Bird

Hold the switch, and rap under the door with a mallet.

Lagonia

If you end up having to replace the window motor..... get ready! It is a job! The door internals need to be gutted, window removed etc. The motor and regulator need to come out as one unit before you can fit the new motor on the regulator since there is a tension spring involved. I am in the process of doing this job myself.

Big2Bird

I changed both motors last summer, and I did it with everything in place.

drwet

I've had my doors apart so many times its hard to remember exactly what I did each time, but I'm pretty sure I have changed a motor without completely removing the regulator, but don't ask me how I did it.

The Money Pit

Years ago I replaced the motors with the regulators still in the doors, I don't remember it being that hard.....Last year when I did the regulators and the motors, the first one blew apart in the door,....and I had no idea what went where, because I had never seen it together. That side took me all day. The next day I did the other side in an hour..........

The question remains. Is there a connector under the dash, or in the kick panel that would allow me to test the window motor without having to undo the door panel. In all likelihood, I'll need to tear the whole door panel off, but I was hoping I find a broken wire that could be fixed without pulling the whole thing apart.

Peterbuilt

It would be best to remove the door panel.
You can then try the hammer trick.

Then remove the two wires at the motor and check for 12 volts on each wire.
With the switch down check for power on the BROWN wire.
Then with the switch UP check for power on the DARK BLUE.

Next, GROUND the motor case and apply 12 volts to one side of the motor plug and then the other and see if the regulator is binding.

7T1vette

The motor is probably the least likely cause of your problems. If you did not change out the window switches...or, even if you did...the switches can have their contacts carbon-up from long-term switching of window motor power. Without a relay in the system, significant amperage is transferred thru those switches. You may be able to remove them, clean the contacts and just replace them for many more years of service (if that is the problem).

Another possibility is that the wiring transferring from dash to door can fail in 'fracture' mode from many cycles of opening/closing the door.

Your best diagnostic is to find where there is a break from the power source, in that wiring circuit. Ground wiring is just as important as power wiring.

drwet

Removing the door panel and testing at the motor is probably your best bet. Even if you find a connector under the dash that you can tap in to to test, it won't tell you if the wires are intact to the motor and I still think that is one of your most likely scenarios.

Big2Bird

The only thing I can think of is pull the console trim panel, slide off the connector from the switch, then test there.

Lagonia

Removing the door panel is not as bad as you might imagine. Get to the connector where the arrow is pointing and then you will have your answer - it is either the wiring to the motor or the motor itself.

Peterbuilt

In post #1 you indicated a voltage drop when powering up the switch.
That tells us that the wires are good and the motor is bad or the regulator is bound up.

7T1vette

You cannot test for a bad switch with a simple ohmmeter as it will show continuity even if the contacts are carbon-covered (there is an increased resistance, but it is fractions of an ohm). But when such a switch is trying to pass high current, the resistance of the carbon can cause the motor to run very slow...or not at all. If you open the console, remove the switches and carefully un-bend the swedged areas which are used to assemble it. Remove cover (carefully so as to not lose the springs; also take careful note of how it is put together). If the contacts are burnt, clean them with ScotchBrite and coat them well with a protective, non-conductive electrical grease. This will help in minimizing future burning of the contacts.

Rotonda

Post #2 describes the problem I had. I diagnosed it by peeling back the rubber boot that carries wiring from the door jamb side and pulling on the dark blue and brown pair. There is some (not a lot) slack in the harness and it was enough to expose (and repair) the break in the brown wire.

If these wires are intact, it exposes them for you to probe and test with minimal work to restore.