I'm really scratching my head on a motor that won't work at all. I was wondering where it grounds at? Thanks.

 

In your original post you should include the year of your Vette.

If this is the two wire type motor, the headlight control module provides the 12 volts to the motor. Depending on the polarity of the voltage will determine if the motor goes cw or ccw.

So to answer your question, the headlight control module determines which wire is ground and which wire will get 12 volts.

The control module is bolted to the front of the driver side black plastic wheel well housing.

 

Sorry it's a 91. If I unplug the offending motor, the test light works like it does on the side that works fine. If I plug the harness back in, both wires have juice and the motor will not work at all. I tried changing the module and plugging in another motor I have and neither helps. I'm stumped.

 

Here's some questions.

1)Which headlight door motor doesn't work?

2)Can you manually turn the black **** on top of the motor and manually open and close the headlight bucket? Action should be smooth with no binding. It takes alot of **** turning.

3)If you disconnect the motor plug and apply 12 volts from the battery direct to the motor does the motor work? If you change the polarity does the motor turn in the opposite direction?

4)If you have an ohm meter can you compare the resistance of the motor that doesn't work to the one that does?

If you have a volt meter, disconnect the plug at the headlight control module and verify these voltages at the plug. Becareful some of the wires are hot all of the time.

There are 2 red wires. Both should have 12 volts.

Black wire is ground and should have zero ohms to the negative battery terminal.

When the headlight switch is off, the white wire should have 12 volts.

When the headlight switch is in Head position, Yellow wire should have 12 volts.

Gray/Black wire and Dark Green/Black wire go to the
Left hand /Driver side headlight motor.

Gray wire and Dark Green wire go to Right Hand/ Passenger side headlight motor.

 

Alright, just got done going through the list:

1) Which headlight door motor doesn't work?

Passenger side. Will not go up nor down. Motor does not run at all.


2) Can you manually turn the black **** on top of the motor and manually open and close the headlight bucket? Action should be smooth with no binding. It takes alot of **** turning.

Yes. It turns smoothly. I can open or close the door with no binding.


3) If you disconnect the motor plug and apply 12 volts from the battery direct to the motor does the motor work? If you change the polarity does the motor turn in the opposite direction?

Yes and yes.


4) If you have an ohm meter can you compare the resistance of the motor that doesn't work to the one that does?

Resistance is the same on both motors and the spare I have.


5) There are 2 red wires. Both should have 12 volts.

They do.


6) Black wire is ground and should have zero ohms to the negative battery terminal.

It does.


7) When the headlight switch is off, the white wire should have 12 volts.

It does.


8) When the headlight switch is in Head position, Yellow wire should have 12 volts.

It does.


- Gray wire and Dark Green wire go to Right Hand/ Passenger side headlight motor

If I unplug the the wires at the passenger fender, the two wires coming from the module will come on and off just like they should. They will work exactly as the other side does when the light switch it turned on. If I plug the plug back into the motor, both wires have juice no matter what and the motor does nothing. The same thing happens with the spare when I plug it in. (The spare is a used one I bought off ebay.)


Help please.

 

Try this.

Headlight switch off. Hook everything back up and manually turn the passengerside headlight bucket to the closed position.

Disconnect the negative battery cable for a couple of seconds and then reconnect it.

When you reconnect the battery cable do you hear two thumps. One from each headlight motor?

 

Did that, only one thump from driver's side.

 

I sent you a PM