Strange Problem With Power Windows

[wntrwlf]

This is a 2000 Infiniti QX4. The Driver window rolls up and down 100% fine. The Front passenger window rolls down fine, but is extremely slow rolling up from the master switch only. The front passenger switch will not roll its window up or down at all, no noise no nothing. The rear windows will roll up and down both extremely slowly from the master switch, but from the rear switches the windows will only go down about an inch and need the master switch to lift them back up all the way. These problems started with the front passenger window rolling down from its own switch, and needed rolling up slowly from the master switch.

I have replaced the motor and regulator in the Front Passenger door, only to find that it has the exact same problem.
I have cleaned the tracks to make sure the window isn't getting stuck.
I checked fuses and relays.

I do not know how to diagnose electrical issues, but I do feel capable of learning. I do have a multimeter.

My best guess is that the master switch needs replaced, possibly the front passenger switch as well, and the motor and regulators need replaced on both rear windows.

How can I diagnose electrical issues/switch issues, before I spend $250 for a master switch, $45 a piece for passenger switches, and $130 for rear motor/regulators?

I'd like to do all the work myself but I am a novice at issues like this. My only other option is to have a shop fix all the windows quoted at $250 per window.

[MisterH]

The first thing I'd try is removing the master switch panel and thoroughly hosing down the individual switch contacts with a high quality contact cleaner like Deoxit 5. If that doesn't help then you could get a complete used master switch assembly off eBay. I've seen ones that look to be in perfectly good shape for $50-60.

[A1218]

I was having similar issues and it was the master switch. I did try cleaning it but that did not help.

I was able to find a new one on carparts.com for less than 30 bucks. I know its a cheap Chinese product but it looks exactly OEM and functions well. Solved the problem.

[VStar650CL]

I was having similar issues and it was the master switch. I did try cleaning it but that did not help.

I was able to find a new one on carparts.com for less than 30 bucks. I know its a cheap Chinese product but it looks exactly OEM and functions well. Solved the problem.

+1. Crap like that is almost always an issue with the "default" ground contacts inside the master switch. You should also check the pins on the master switch and its connector, they've been known to heat up and blacken.