Trailer Running Lights Are Dim When Connected to 2008 Volkswagen Passat Wagon with LED Lights

Question

Question:

I have 2008 VW Passat Wagon not the 4 motion. LED lights for tail lights. I had a wiring harness professionally installed. The running light are very dim. I replaced the complete set of lights on the trailer and even ran a separate ground directly to the lights. I followed your instructions to test the wiring directly. The turn lights and brake light have plenty of light. Given that the car has LED lights in the back my suspicion is as follows 1. The running lights are running from the running lights on the car and do not have enough power to light my trailer lights 2. There is a wire running directly to the battery in order to feed enough power to the brake and turn lights via the module and they work fine. 3. I suspect I need a module that allows standards lights to be fed by the main lead from the battery. 4. I tested it also with LED lights on another trailer and the lights are ok much brighter when I tried it on a another regular bulb trailer the same problem occurred. My question is will your module give enough power to light the running lights with standard bulbs or do you recommend to change my lights to LED lights.

asked by: Guy C

0

Expert Reply:

A vehicle that has LED lighting, which draws much less power than standard incandescent type lights, will also have lighter gauge wiring that may not be able to pass enough current for incandescent lights on a trailer.

This is why trailer wiring harnesses like the Curt # C59236 that you referenced are made with a separate 12V power input wire (that goes to your battery through a fuse). This direct battery connection is what actually powers the trailer lights. The vehicle wiring cannot pass enough current.

The vehicle wiring and signals are used essentially as a switch to tell the converter to send out the appropriate lighting signals for the trailer, which are actually powered from the battery connection.

This is why your turn and brake lights work but your running lights are dim. Always-on running lights need much more power than turn or brake lights which are not on 100-percent of the time.

The Curt harness # C59236 has a fairly high current output capacity - 5 amps per stop/turn circuit and 7.5 amps for the running lights. If your current harness has a lower rating, then replacing it should correct the issue. You can locate the unit installed in your Passat and compare its power output rating, which should be indicated (or you can obtain the part number from your installer). If its output is substantially lower than the Curt, then replacing it may do the trick.

Replacing your trailer's lights with LED types is another option - although you could do both - both upgrade the harness (if applicable) and swap your trailer lights for LEDs.

The link at right will let you see all LED-type trailer lights and you can use the filters in the left margin to narrow the results based on your requirements.

expert reply by: Adam R

0

Trailer Running Lights Are Dim When Connected to 2008 Volkswagen Passat Wagon with LED Lights

Product Page this Question was Asked From

Featured Help Information

Instructions

Miscellaneous Media

Continue Researching