rear window switches work, sometimes (not regulator issue)

[nbishop]

Any advice on diagnosing sporadically working rear windows? I've replaced the master switch, the single switch at each of the rear doors, and both regulators. One side will work after rapid flipping of the rear door switch, the other works randomly, maybe once a month. I have the FSM but did not find useful guides on moving past this point. THANKS!

Nick
1997 Montero LS

 

[Salonika]

Broken wire? Have you tried diagnosing this problem while having someone open and close the door at the same time?

 

[nbishop]

Broken wire? Have you tried diagnosing this problem while having someone open and close the door at the same time?

I haven't tried that yet. I've pulled back the rubber sleeves that cover the wires at the door jams and didn't see and visual indication that they were broken there. I'm guessing the next step is using a multimeter or a test light to identify the wiring as problematic.

 

[BOPOH]

check for corroded connectors, all the way to main fuse box