need help quick with trailer lights

when the headlights are turned on, both side marker lights and both tailights come on. however I don't have any turn signals or brake lights?? I've tried with two different trucks today and same situation. where do I need to look??!! thanks in advance.

Re: need help quick with trailer lights

to help clarify, the lights are mounted to the frame directly. if i pull the light off then of course it goes off. I tried pulling the light and running a ground clear up to the plug ground and nothing changed. still just running lights with no brake or turns. please help, i wanna head to the lake in an hour!!!

Re: need help quick with trailer lights

Verify you have turn signals on the truck. You need a test light or voltmeter. The brown wire in the harness works the tail and running lights. Yellow and green run the turn/stop signals. You know the running lights are ok so the problem is either at the truck or the trailer. You can do either one first. If you have a battery charger, connect the ground lead to the trailer frame (good ground). Put a nail in the positive lead and touch either the green or yellow wire pin on the trailer plug. If both lights work the problem is in the truck. If neither works, the problem is with the trailer. Then test the same two terminals on the truck -- but you'll need a voltmeter or test light. If the truck harness doesn't work check the truck wiring.

Re: need help quick with trailer lights

hope you fixed the lights before heading to the lake...but if it's not too late...

Taillights/sidemarkers stay on when you step on brake? Plus your other test of ground circuit makes me think ground is ok.

First, with test light or multimeter make sure power's coming out the vehicle plug, green and yellow wire, with brake depressed or turn signal on. (I know, two vehicles same result but what a waste of time looking for fault with no juice in the circuit).

No power from the vehicle, could be blowing fuses...if there's a short to ground somewhere in the circuit it could very well blow soon as you step on the brake, both vehicles...lotsa trucks have separate fuse circuit for trailer brakes & turn signals. Assuming it's not that...

Test light with sharp probe will come in handy...connector is most likely suspect, so test the green & yellow wires just beyond the connector...

No tester of any kind, use a couple pieces of wire first to power the lights directly from the vehicle plug...if that works connector is most likely suspect...I'd cut the wires & jumper over the connector & hope that works. replace the connector later.

That's my emergency plan, anyway...

If it's not the connector, 2 possibilities: 1. your green & yellow wires have lost insulation somewhere and contact the trailer...grounding out the lights. You have to either trace it down and repair, or replace the harness. or 2. your green & yellow have both broken wires inside the insulation...I think less likely than #1.

good luck

Re: need help quick with trailer lights

yes they were fixed b4 heading to the lake. I hate to admit this but it was bad bulbs. I had bought the lights just 3 weeks ago for another trailer and they worked fine. I left the lights plugged in on the test run to sell my other rig just to get in and out in a hurry for the guy and it blew just that half of the bulbs. Crazy crazy stuff. thanks again and I shoulda checked them first thing and not taken them for granted. thanks for the quick replys though!

Re: need help quick with trailer lights

hmmm, maybe it would be easier to unplug the lights when you put the trailer in water. It will stop the lights from going out.

Re: need help quick with trailer lights

i normally do but thought, ah, what's one time gonna hurt. yep.....

have a good one!