Working inside the doors, questions and explanations

[Jonathan]

The weather here just might be thinking about warming up soon, so I figured I better get my car put together again.

I still have the inside panels off of both doors. I put a fully charged battery back in and tried the driver's window. This is the original window motor/regulator assembly (the passenger side has a newer replacement and works fine). What I am seeing is that the driver's window is fairly slow going down, but is absolutely crawling trying to go back up. And it won't completely go all the way like it just has no oomph whatsoever right near the end.

I looked at the motor/regulator assembly while it is still installed in the door and it looks ok. Nothing obviously cracked or bent or unplugged. I did notice one of the screws that would likely hold it secure is not there. There are a couple others in that central spot holding it tight enough that it doesn't pivot or more anyway. I also unplugged the two wires connected to it, pulled them down to inspect (they look ok) and then clipped them back in. It's a tight spot to get your fingers in there, but they seem plugged in the whole way.

Still no change. Slow as molasses going up. Just like it has no 'battery' power left like a cordless drill would just slow down to nothing if that drill's battery was drained and needed charging. It sure seems electrical. I would guess it is something to do with whatever 'windings' are inside the assembly and not a mechanical gear issue like it's jammed somehow. I swapped the switch from the driver's side to the passenger and saw no change. I have the new LED backlit window switches so not really thinking they are the problem.

The two wires going to the assembly are blue/grey and red/grey. I don't see any other wires. Is there supposed to be a ground somehow for the window motors? Is it possible that a missing screw in the bracket is causing a grounding issue? Is that even how they work?

I am asking mostly because I'd like to ensure a new window motor is needed before ordering one. I can't really afford a whole lot more parts for the car if they're ones I didn't really need in the first place. $300 for the window motor is reasonable but not cheap. Not like buying windshield wipers or oil filters. Thanks.

[David T]

The motors do not require a separate ground. They work by applying a voltage and ground through the 2 wires and to reverse it the polarity is just flopped. That said it is possible the windings are burnt and some of the electric is draining out of the motor to ground. More likely the window is binding up but at this point the best advice would be to just upgrade the driver's side window regulator and motor to the newer style. Then figure out if the window is binding. Once you take the regulator out you can move the window by hand and see what the problem is. If you want to continue testing the regulator/motor just apply voltage and ground directly to the motor wires.