Q: Rear right power window does not lower (go down) on 1994 Toyota Camry

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The rear right window on my Toyota Camry 94 is failing to lower (go down). I bought a brand new regulator/motor assembly and before installing it I tested it by connecting the harness and operating the switch. The regulator operates well while raising the window but it does not lower it. I repeated the test with the switch from the other window (which is operating correctly in both directions) and it also failed to lower the window with the new regulator. So, in conclusion it looks like the problem is neither with the regulator/motor assembly nor with the switch...
Any tips to help find the problem area and fix it will be highly appreciated.
(2) Answers
(1) Comments
wiring sounds like the problem you will be chasing.
look at the wires going down to the motor and make sure nothing is broken or frayed anywhere.
difficult to diag here in this forum without seeing it.

I was affraid to admit it was the wire.... So I tried first with a new master switch (Switch Doctor - great service and very reliable) but unfortunately the new switch didn't resolve the problem either. So now that I know it is a problem with the wire harness, I don't know where to start... How to diagnose where the wire problem is without tearing up the entire car interior? Any advice will be really appreciated.