Hello everyone,

I have an issue that since today nobody can't fix it and they start telling me about rewiring the whole right side.

My right rear tail light - the red when you open the lights - doesn't get power. Fuse is fine, bulb is fine, and when I move the light to the other side and plug in the power it's working fine. I don't get any warnings. I tried everything so far including cleaning, removing the battery etc.

Any idea would be strongly appreciated!

 

Start at the rear with a voltmeter or test light and start working your way forward until you find where the voltage stops. Dunno what's "unbelievable" about it.. poop happens.

 

You have any idea where the cables starting from the front?

 

Dunno from that end - but probably from the body control module. If they pass up through the bundle under the carpeting on the starboard side (passenger in the US), it's possible there is water under the carpeting and the connections have corroded.


Best technique is to start at one end and start following the wires - rear is easy since you know where that end is.

 

I had a 2000 Grand Cherokee with brake light problems where the plastic bulb sockets melted and opened the ckt to the bulb. I bought a til light housing on eBay and it did the same thing a year later. I ended up having to solder copper wire jumpers around the contacts to avoid having to buy new tailight housings.

 

Great suggestion except he swapped lights, and the problem didn't travel with the light.. so.. it's wiring related.

 

Good point. But wiring seldom fais open. There is probably one wire feeding several wires supplying various rear lights. From what he says, it seems likely the problem is at a connector in the back somewhere.

 

Actually - auto (and motorcycle) wiring quite often fails open. Too tight a tie-wrap on a wire that moves a bit - and it will eventually fail due to metal fatigue. Hatch wiring on euro cars is notorious for doing this where it flexes when the hatch is opened. BTDT on a number of German cars..


The wiring for the rear lights runs across the rear of the spare tire compartment (from memory..) so it might be worth checking especially if the upstream light is out (last light on the wiring chain..) and the other light is working.


Testing is pretty simple - you can do it with a $2 trouble-light from Harbor Freight. Start at the end where it isn't working and start following it back towards the source. Could be wiring, could be a connector. In either case there are no real shortcuts to diagnosing it since it hasn't been a "common failure" from what I've seen on numerous Cayenne forums.

 

Seems to be some confusion here.
Let's start again.

Does your rear right turn signal work?
Does your right stop light work?
Does your high mounted stop light work?