Sunroof motor wiring

[rafik dous]

Car is a '73T

Looking for help to get my sunroof to operate. Maybe a sunroof wiring diagram will help
When the motor is hooked up, it does not work in either directions

Motor is fine. Removed it. Connecting the yellow and blue wire directly to a battery operates the motor fine. Reversing the polarity reverses the motor direction. So far so good

Tested the switch, it's fine

Power to the switch is fine

Traced the two wires (yellow and blue) with an ohm meter from the motor back to the switch, they are both fine

What I can't figure out is where the motor is getting its ground from? The two wires (yellow and blue) are positive from the switch depending on the direction. So I thought the grounding must come from bracket where the motor is bolted. But the motor won't operate if I ground its case

What am I missing? Sorry if it's a stupid question, first time I repair a sunroof

Thank you

[letsrollbabe]

Here is the wiring diagram for a 75, and yours is probably the same. The ground and +12V are switched each time the toggle is switched, so the wires to the motor alternate between being a ground and being +12v as the toggle is switched. I am having a problem with my 75 similar to you though, and like your car, my switch seems fine, there is 12v at the switch and one line at a time going to the motor...but it won't energize the motor. The middle post is ground on the toggle, and the 12v switches between the single post to each end post as the toggle is worked.

[rafik dous]

Thank you, very useful
I think I figured my problem out. The switch should have a ground on pin #3 but mine doesn't. Which is very strange because the loom is original and hasn't been hacked. See the picture below, no ground
When I grounded #3, the motor works correctly