[CWorthington09]

04 SDN V6 Auto 4-motion
I have a repair manual.

My socket housing only uses 3 bulbs, odd considering my 02 used 4.

Anyways, I checked fuse 31 (15 amp) and its good. I get power when the ignition is turned on. I put the vehicle in reverse and the lights do not light up. I checked the Blue/ Red wire on both side and get battery voltage when vehicle is in reverse. They go out when not in reverse. I checked the brown wire for the ground and i appear to be having a issue. 7.2 ohms on the driver side and .4 ohms on the passenger side.

Where is the ground locations at?
What other tests should i be doing.


Side note: Driver side rear side marker not lighting up but passengers is.

I appreciate any and all help.

 

[Electron Man]

Seems you've isolated the issue (bad ground on the driver's side bulb).

Double check the Bentley page the wiring schematic is located on - they usually list ground locations. Otherwise, you're playing "follow the wiring harness".

If you've carried something heavy or bulky recently, that object may have "jacked up" your driver's reverse bulb ground wire.

Good Luck

 

[CWorthington09]

Nothing heavy was carried.
I don't have the Bentley I have to the other cheaper shop manual, it doesn't tell me where the ground location is. I don't understand why the passenger side isn't working if it has a good ground. The rest of the tail lights working though, including turn signals.

 

[CWorthington09]

Bump.. Still working on this. I'm not sure but seems like the ground location is in the driver side kick pannel next dead pedal. I'm going to dissconnect to confirm..

 

[CWorthington09]

After discconnecting those ground points nothing changed and I still had resistance. But I pulled up carpet and found yet another ground. More than likely goes to ccm but disconnected it anyways. After doing that in most resistance for driver side. I'm getting nothing at all OL . Passenger side is still there. So I reconnected it and I continued to get nothing passenger side still the same.
I'm going to try connecting the assembly right to a good ground and checking to see if it works then.

 

[CWorthington09]

With the passenger side disconnected and the driver side ground disconnected and the flashers on, the rear brake light dimly flashes and the third brake light flashes brightly. I'm beyond stumped on this nightmare. I'll be turning it over to some one who is supposedly good with wiring.

Thanks to that one guy who chimed in...

 

[CWorthington09]

Got it all figured out... So in like the 1.8t the 2.8 4motion has different tailights. You have to remove the actually tail light to get to the reverse light bulbs. Maybe it's because of the year? Anyways, I believe my other issues were related to a fail safe design in case something happens the brake lights will become the flashers.

I found the passenger side had no socket for the reverse side and the drivers was burnt out... Got a new socket and bulbs and all is well.