Trailer Wiring Problems, Running Lights, Brake Lights

Stuff I have done prior to this post. I have the trailer hooked up through the 4-prong plug, Another set of trailer of trailer lights I've tested as well, checked all fuses in both vehicles. So now heres my problem. Everything seems to work perfect (Brake lights, Turn Signals) on both vehicles... UNTIL I try to turn on the running lights. Once running lights are switched on (Jeep) none of them turn on but brake & turn signals still work fine. Now When I switch on running lights (Truck) they turn on but seem to mess up everything else(brakes, turn signals, including the trucks rear turn signals, plus the running lights blink too.) Also when they(running lights) are turned on and brake is pressed, all of the trailer lights turn off but take my foot off the brake and all lights come back on(this only happens on the truck) (see Video.)




Basically if I didnt have to haul this at night I'd be fine but in order to be legal I need to get this fixed.

2000 Jeep Grand Cherokee, 1999 Dodge Dakota. Trailer Running Lights

Category:

Autos & Vehicles

Tags:

• Trailer Wiring Problems
• Running Lights
• Brake Lights

[djshorty8604]

Ok well just to inform everyone, there was no bad ground, it ended up being the wiring module. Thx

[computersshot]

Or it could be a bad wiring harness on truck

[computersshot]

it's a bad placed bulb when twisted on i think

[fiveisaacs]

@djshorty8604 are you talking about the wiring module on the truck by the connector? can you be more specific as i have the same problem you are having. Thx

[dorin2042]

Bad ground on trailer. The jeep has the trailer parking lights fuse blown.

[formerkillerz]

bad ground



[mjc8bal]

Bad ground

[vhanktank]

I have a very similar problem on an '85 Chev C-20 P.U. Trailer checks out fine with brake lights and turn signals, but running lights won't work. Having tested the leads, I am convinced the problem is with the truck and not the trailer. Since the tail lights, license plate light, etc. work on the truck, itself, I have concluded that it must be one of two things: a defective connection or wire or plug connecting the tail light feed to the plug-in; or I am not getting a ground on that circuit.

[apintonut]

bad ground on trailer