Troubleshooting Taillights with a 7-5-way Adapter on an Audi Q7

Published 10/05/2012

Products Featured in This Question

Hopkins Wiring Harness with 5-Pole Flat Trailer Connector - Vehicle End - 5' Long

(17)

$10.16

Hook Probe Circuit Tester

(72)

$13.14

Question:

I have an Audi q7 which has a trailer light adapter with a 7 blade input. The trailer comes with a 4 pin adapter. I bought an adapter that connects to the 7 blade, but it has a 5 pin connecting side instead of 4 pin. I was told it would work by plugging the 4 pin into the 5 pin and leaving the top pin empty. The right tail lights do not seem to work, nor is the right signal. Does this have anything to do with the 5 to 4 pin issue. By the way, the Audi lights are on auto when I am running the test. Thanks

asked by: Howard

Expert Reply:

The issue you are having is not a 4-5 way adapter issue. If everything was working correctly using a 4-way on a 5-way connector would work just fine.

I would first just try pulling the adapter out and re-installing it just to see if maybe something is making good contact. If that does not fix it you will need to use a circuit tester like our part # PTW2993 to test for voltage first at the back of the 7-way on your Audi Q7. If there is voltage going into the connector but not out of it you know the problem lies in the wiring of your vehicle and will need to be addressed.

If there is voltage coming out of the connector but not through the adapter then you know the problem is somewhere between the connector and the adapter.

If the tail lights of your vehicle are illuminating when you are testing it the trailer lights should be also. It should not matter if your lights are on auto or not, but just to eliminate that variable you could try it without the auto feature. But just to rule it out you might try testing them by having a friend apply the different tail light functions.

expert reply by: Jameson C