Ok so my factory trailer harness stopped working so I went out and got a new one and I got it wired up but I don't have lights when the headlights or parking lights are on but I have turn signals and hazards does any one know what would cause the headlights not to work but everything else to work? The wires on the factory harness are white brown/white yellow and green. I know that the right turn signal is green and the left is yellow or vise versa but can't figure out why I don't have lights when the parking or headlights are on. I need this solved soon cause I'm moving and fixing to be towing a trailer and have to have lights so I don't risk getting pulled over.

Thanks guys

 

I'm guessing a ground or a short somewhere. Check all yours wires with a voltmeter when the lights are one and see what you get.

 

Your description is not clear but I think you are asking how to get the trailer's park/running lights to work, correct?

If so, first check the #5 fuse in the underhood Distribution Box. If that's OK, it could be the Park Lamp/Trailer Tow Relay, also in the Distribution Box. You can do a quick test on this by swapping with another identical relay in the box. Beyond those, you're probably talking about a problem with the brown/white wire or its connectors.

 

I suggest doing what bob said. My guess is a fuse or relay is bad.

 

Yes bob that's what I'm saying when I connect the test connector to the harness on the truck I get the lights for the turn signels and hazords but when I turn on the park/headlights I don't get any thing. I will go out and check the fuse under the hood later cause it's of as hell out side right now and will post what I find out. Thanks for the info

 

Could be a short...when I got my truck, there was a bunch of corrosion on my 4-flat connector. Seeing as I work at Uhaul, I got a new connector with a 60" lead, it also has signal test lights in the connector...Pretty easy install. Just a pair of pliers and maybe a pocketknife. Costs about $8...I'll take a pic of it soon.