Access the switch and check for 12vdc being applied to the motor when the switch is toggled. If that works, check the winding resistance of the motor. Compare it to a known good motor in the other rear door. Check for binding or damage to the lift mechanism.. If all checks out okay, report back.
Do you hear a single click or a bunch of noise, like clicking and grinding?
The thing to do is to get yourself a test light and remove the door trim panel.
I disconnect the motor connector, put the test light accross the connection on the harness end and reconnect any wires to make the switches work. Then hit the switch up and down. If the test light lights up in both directions then the problem is the motor/regulator. (sometimes you have to replace the regulator depending on the design) On an '01 Deville I think that has a cable regulator. I just replace those in one piece.
If the test light does not light you have to check more stuff.
If you have the skills to make it that far, let me know and I'll help you some more.
The click might indicate that the switch is working, but as I said there is only one way to know for sure and that starts with taking the door panel off.
What does it do when you push the switch on the door in question?
It could be a door control module, but like I said, you need to get to the connector with a test lamp.
The relay could be clicking and trying to run the motor but the motor could be bad, not responding to the power.
In the old days I'd tell you to smack the door reallly hard (don't break anything) while holding the window switch and see if it starts working.
I pulled the panel and tested the motor and it worked fine. I can't find my test light but I hooked up the switch from the passenger side and it did the same thing, it just clicked. I noticed the clicking noise is coming from a module that 3 other harnesses are going to. So I hooked up the module from the passenger side and it did the same thing.
So if it isn't the motor, regulator, switch, or module --- what can it be?
Check the harness were it goes through the door. Pop the connector out where it goes into the door post, disconnect and inspect the wiring right by the pins. I had the same problem with my 2000 DHS where it would just click when you hit the button and it turn out to be the ground wire broke on the door side of the pass through connector.
This thread is spot on. I had a friend come down today looking to change a regulator in the LR door of his 04, knowing I'd done this many times before. I got the door apart and said OK, run the windows down so I can get the regulator out. When he told me the windows doesn't move that's why we're doing this, I began to worry.
I thought about it for a minute and said huh, the motor must be bad. No problem, I have one in the garage. Although my motor ended up being for the opposite side, we plugged it in to test. Low and behold, nothing, so I worried more.
I came inside and found this thread then it all came back to me. My 01 DTS has the same issue. Sometimes the LR windows doesn't work. Sure enough we took that connector apart and BAM, there it was, plain as day, a broken ground wire.
Now I want to ask, when you looked at yours was the wire kind of fraied and look like it had broken from the continuous bending or did it look like a very clean break, almost like someone had cut it with a pair of snips?
I had the same problem this morning. The left rear passenger window would not work. When you hit the window switch you heard the click but nothing. So I started wiggling the harness that passes thru the door as I was holding the switch and the window worked! I could control the window at will by wiggling the harness but it won't work otherwise. So at least I know what's wrong with it and probably has a broken ground wire in the door pass thru harness.
I am having the same problem on a 01 Deville, the module just clicks. I bought a new motor and regulator and took a module from my other working rear window. None of my wires are broke and I even put a ground onto my door to check if that will help and it didn't. Any other ideas on what I might be missing?