both windows dead after replacing passenger regulator, all fuses good
Replaced the passenger side window regulator/motor on a 2009 Aygo (LHD). Before swapping, I probed the yellow 2-pin motor connector with ignition on and got a clean ±12V both directions, so wiring and switch checked out and the old motor was clearly the fault.
New regulator tested fine on the bench. I then tried wiring a second switch in parallel so I'd have two switches for the same window. After that, nothing works: at the motor connector I now get a brief 12V that drops to 4-5V and holds there. Driver's window worked earlier and is now dead too.
Checked so far:
Battery good, radio and wipers work normally
Pulled all three cassette fuses in the engine bay box (30A pink for power windows, plus the two 40A) — all three beep for continuity, none blown
Reseated them, no change
I'm now assuming the parallel switch wiring is the culprit — as I understand it these switches pass the motor leads through and ground both sides at rest, so paralleling a second switch ties a 12V line straight to ground. Undoing that is my next step.
Anyone confirm that's what's going on? And is there actually a separate power window relay on the LHD cars, or do they run straight off the 30A fuse?