Does installing an aftermarket 5-pin trailer harness require computer re-program?
I'm thinking of installing an aftermarket trailer hitch on my 2014 Evoque. The trailer requires a 5 pin (aka 5 pole) wiring connection because the trailer has "surge" or "inertia" brakes. In this situation, the 5th pole is required to de-activate the trailer brakes when going in reverse (so that the trailer's brakes aren't working against you).
To accommodate this, eTrailer.com has suggested I install a 4 pole wiring harness (C56159) into the factory quick connect. Then I'm supposed to use a 4 pole to 5 pole adapter (part # 47515). The adapter splices into the car's reverse light, so that the trailer brakes are de-activated when you're going in reverse (which is what is supposed to happen).
That all sounds fine, but one mechanic I spoke to said I would need to reprogram the car's computer after splicing into the reverse light. Something about how the onboard diagnostic system will detect current being drawn off the reverse wire. This might cause an error message on the dashboard. Anyone have any experience with this? I asked a Land Rover dealer service shop and they said they can't comment on after-market parts. I wouldn't mind so much if an error message appears only when towing, but if it's on all the time that's a deal killer.
03-31-2015 02:50 PM
I just had the hitch and wiring installed at uHaul ($90). So far the car is not producing any error messages. I have not tried it with the trailer on it, but so far it appears the answer is that a computer re-program is NOT required.
I have towed a trailer with surge brakes with my Evoque no problem using the 4 pin to 5 pin adapter. This was on a 2014 Evoque. Reverse was fine. No error messages. No issues whatsoever.
I have a 2012 and the new adapter fits perfectly and works fine. However some built in features do not work. For example the parking assist (object warning noise) should be disabled when in reverse. I suspect the issue to be with my trailer as it has LED lights and the evoque may not be able to detect them. This issue is documented in some evoque user manuals but I have yet to find a work around.
Originally Posted by Engineer