After Installing In-Bed 5th Wheel/Gooseneck Trailer Connector, Only Running Lights are Working

Updated 02/10/2014 | Published 02/09/2014

Question:

i have a 2003 f250.i installed this kit very simple which was great.i hooked up my new big tex gooseneck trailer and the only lights working were the running lights,i have no brakes or turn signals.....any ideas

asked by: David N

Expert Reply:

You will have to make sure that the alternate ground wire on the Hopkins in-bed trailer connector, # 41157, is attached to a clean bare metal surface on the truck frame. If it is not then the harness will not work correctly. You can also try different grounding locations that could give you different results.

If everything is installed correctly and you have a strong ground location, unplug the trailer and use a circuit tester, such as # 3808, to test the connector while someone sits in the truck and runs through the various functions. If they are not working, disconnect the harness and plug in the factory wiring like normal. Then test the factory connector.

If the factory connector works without the other harness connected, that indicates a problem with the in-bed harness and connector and it will need to be replaced.

If the factory connector does not work that indicates a problem with the truck wiring. It could be anything from a blown fuse or relay to a dirty trailer connector, to a broken wire. These are the most common issues that you can check.

I have also seen issues on trailers that have junction boxes. Wires can corrode or break loose in these boxes so if the trailer has one that is something else you can check. If everything does work on the truck side then the issue must be on the trailer. If not the junction box then it could be a weak ground, corroded connector or broken wire on the trailer side.

expert reply by: Michael H