Reverse switch - no power

Felix B

Registered User
Nov 17, 2018
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Hello all,

Done all the usual stuff I could find suggested online, new bulb, checked every fuse, new reverse switch, checked for power and broken wiring to reverse switch. Still nothing.

I have determined that there is no power going to the reverse switch. Only pin 1 (Blue/Black) has any form of detectable resistance to ground and it's around 1MΩ.
So, I assumed pin 2 (Black/Green) is for power and is simply broken and is an open circuit. I've stripped back the protection all the way back to where it splits into a Y-joint near the nearside headlight and appears to continue back through the firewall and then splits off into one of two directions, the ECU or behind the instrument cluster. Does anyone know which of these two this wire is supposed to terminate? (Hoping not the ECU because that looks like a pain to remove from a few YouTube videos I skipped through).
Because I was a little desperate I checked for continuity between each pin in the connector and poked a tiny hole with my multimeter probes through the insulation just before that first Y-joint to make sure there wasn't a hidden break within the insulation, but unfortunately it buzzed out on both wires. I find it hard to believe there could be a break any further up the harness as everything appeared to be so well strapped down.

Haynes manual reckons the reverse switch power comes directly from the passenger fusebox fuse (FC4) (Heating, Air conditioning and some other things). As I said earlier none of the fuses are bad and my heating works perfectly fine. Also, Haynes reckons the two wires should be Black/Blue and Black/Purple where as my wires are Black/Blue and Black/Green so not sure to trust it.

Absolutely any suggestions would be greatly appreciated. Got some pictures if that helps anyone visualise what I'm trying to describe.