Audi Q7 trailer hitch electrical Brake light problem
 

I recently had my dealership add an Audi hitch, and electrical harness with electric brake controller to my Q7.
When I hooked up my Pop Up Trailer Camper most everything works (turn signals, hazard lights) except the brake lights. When starting the car I get a message that the brake bulbs are out, first on the left side, then both. I took it to the dealer and after 2 days there they toll me the problem is on may trailer camper.
Notes: The trailer lights are brand new, and work fine on a ford f150 pick up truck. They are standard bulb lights (not LED).

Has Anybody else here had the same problem ??

http://wiki.ross-tech.com/wiki/index...trofitting_(4L)
Did they recode after install?
That bulb fail report is typical of not being set for the heavier draw with extra bulbs.
Did they test your trailer on another Audi?
Did they test a different trailer (known to work) on your Q7?
Did anyone check the trailer plug wiring is correct for your Q7?

Sorry I have no definite answers but others have had similar probs. Plenty of web pages re; retrofit hitch, trailer VAG codes, Q7 trailer wiring.

Thank you for the reply !!

The Trailer camper lights all work good when towing with my ford F-150 the problem is when I connect the Q7 everything works but the break light signal. I also get the break light bulb light on the dash. When I'm backing up with the trailer the rear sensors are on and the beeping sound is also on. It seems that the Q7 those not recognize there is a trailer attach to it.

Question ? Do the backing up sensor turn on when backing soothing connected to the hitch ???

No, once trailer electrics are plugged in the sensors go off or at least silent. The MMI screen will show you the traier. I think they still work because when you engage reverse it shows the type of trailer like the sensors can detect if it is a long narrow draw bar or a box and changes display accordingly.
Just check on your mmi control to see if towing mode is active once plugged in. (you can manually set it if you need. Handy for maneuvering without electrics plugged in (boats).
I suspect the coding is wrong as you have two problems showing up. There are 4 areas of coding to be done!
If the coding is not correct the ASM, anti sway, transmission settings, brake balance and lights (and air suspension if fitted) will not be working properly.
I hope they used the correct module/ plug loom and not used relays or bridge connectors.

The only reason I mentioned testing another trailer was in case your trailer and F150 were wired compatably to each other but not Q7.

I don't see in the MMI control the towing mode :mad: Is this something it should show in the MMI ?

I'm going to connect a jet ski trailer to the Q7 in a little while with a 7 blade to 4 pin flat adapter to see what happens and report back.

I was checking the Q7 before driving to the storage to try to hook up the Jet Ski trailer to test it and when I plug the "HOPKINS ADAPTER part #47345 7 BLADE TO 4 BLADE FLAT" I get the left brake light bulb light in the dash again... Note: I still haven't plug the Jet trailer to the adapter is only plugged in the Q7 hitch plug.

Any thoughts on this ?

Just got back from trying the Jet ski trailer to the Q7 and I get the same problem rear brake light on the dash again.

I think I will have the same problem regardless of the trailer a connect to the Audi.
This is really pissing me off. My vacation is coming up and I have this problem.:mad:

If you are not getting the Tow option appearing in the MMI it sounds like it has not been set up properly for towing when they fitted the package.

With the factory package mine worked perfectly when the trailer was plugged in and you can also access the Tow option even when it is not plugged in.

Do you have Air suspension ?

yes