Passenger Side Taillight not Illuminating After Installing Curt Wiring On Audi Q5

Updated 03/30/2020 | Published 03/28/2020

Question:

Good Morning, I installed the Curt C56404 wiring harness in my Audi Q5 yesterday and I am having 1 problem and I was wondering if you could help? The install went fine and im getting power to the trailer lights but my passenger side is not blinking or illuminating brighter when i press the brake? I get illumination but no right turn signal, brake illumination or 4 way blinking just on my driver side. So left turn and driver side work fine. Any feedback if you have any would be great. Thank You.

asked by: Todd P

Expert Reply:

It sounds like you have a classic ground issue with the Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer part # C56404 on the 2016 Audi Q5. When the wiring harness does not have a good ground connection it will make the functions act erratically. Some functions will illuminate while others won't. I recommend to take a look at your ground connection and make sure it is attached to a clean bare metal surface of the vehicle's frame.

Also please keep in mind this wiring harness came with a 15 amp in line fuse that needs to be attached to the battery as well. If that ring terminal does not have a good connection with the post of the battery you may be experiencing issues because of that. Please let me know if you are still having issues and we can troubleshoot further.

expert reply by: Heather A