Electrical problems after trailer wiring-help!

rhg

Well-known member
Joined
May 18, 2009
Location
Bel Air, MD
TDI
02 Golf 4dr 5M GLS
After what I thought was due diligence searching the forums about trailer wiring and talking with Curt Hitch Company I installed a non-powered converter box to my lights. I did not short out while plugging the wires into the back of my tail light connections and all checked out well. Drove to U-haul with no problems and plugged into a trailer for a test, all lights on the trailer worked correctly. I unplugged and drove away then the glow plug warning light started flashing, power windows won't work, keyless entry quit,sunroof quit and tailgate won't open. All lights work, fuel door and cruise control work. No bad fuses, fuse links on top of battery good, trailer wiring has been removed. 02 Golf GLS. Anyone know what the fix might be.
 

Vince Waldon

Top Post Dawg
Joined
Apr 25, 2009
Location
Edmonton AB Canada
TDI
2001 ALH Jetta, 2003 ALH Wagon, 2005 BEW Wagon
Certainly sounds like a blown fuse, since a bunch of stuff stopped working.

Did you test the fuses visually or electrically? Electrically is much more accurate, as they can have hairline cracks that are very hard to detect by eye.

The flashing glow plug light is a clue... this often occurs when the car detects a problem with the brake light circuitry.
 

Kombifahrer

Well-known member
Joined
Jan 28, 2008
Location
Philadelphia, PA
TDI
03 Jetta Wagon
I like the fuse idea as well. Those converter boxes are known to be of not of the greatest quality, but I think the result is usually that the trailer lights don't work correctly, not that stuff in your car goes haywire. Would it be possible to remove the box, reset the codes, and see if your problem is solved?
 

rhg

Well-known member
Joined
May 18, 2009
Location
Bel Air, MD
TDI
02 Golf 4dr 5M GLS
I had an OBDII scan only showed the glow plug fault that caused the CEL about 2 weeks ago before trailer wiring. I have a bad glow plug harness.

If I pull the fuse for the keyless entry the fuel door quits so I know that fuse works

When I lock car with the key they pop back open.

I got the brake lights to work by changing bulbs with the blinker bulbs(strange but all lights worked after that). The flashing light also went out on the dash but other problems like electric windows remained.
 
Last edited:

rhg

Well-known member
Joined
May 18, 2009
Location
Bel Air, MD
TDI
02 Golf 4dr 5M GLS
Thanks to those that posted suggestions!

I did a closer inspection of the fuses and found #14 blown. After I changed it the locks still would not operate correctly, I locked and unlocked with the key and then the FOB worked. All seems okay, now I have to decide if I will connect the trailer wire converter box back on or buy the more expensive powered converter that isolates the car from trailer issues.
 
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