# FACTORY HITCH question



## EmbraceEphemeral (Feb 4, 2012)

I recently installed an OEM factory hitch (4L0092101C) on my 2007 Q7 4.2. The hitch came prewired of course, and so did the car. I also purchase the Trailer Hitch Module (4E0907383J) so that everything was a simple plug and play. My problem is the the harness from the car coming into the module shows 13.8v but the output on the trailer control module fluctuates between 2.5-5 volts. Its very sporadic up and down. I would think I should have at least 12v there?
Do I need to have the car physically hooked up to the ball on the trailer?
Do I need all lights properly hooked up on the trailer as well to get a good reading?
The trailer is actually a '65 Airstream that I am trying to test and properly hook up the lights on so I was really counting on getting 12v power to properly test everything.
This is a used trailer control module from that popular car parts site online. Perhaps the controller is bad?

Any insight would be great!
And what would be even greater is if someone with this setup could test the power they have and let me know.


Thanks in advance!


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