Nav. and Brake lights Problem!

[blchandler1981]

I swung my tongue on my trailer over the winter to fit in the garage, and tore open the nav. and the right brake light wires. Not knowing until I headed back from the lake at night, noticed that they weren't working. Got home and repaired the the three wires that were exposed and touching each other, and still does not work. The left turn single and brake light comes on, but not the right signal and the nav. lights. I bought a few nav. lights to see if they were burned out from the touching of the wires since I can not seem to find a fuse for the lights, and still no luck. Does anyone have any suggestions before I have to take it to a dealer (Which they charge 70$ hr)

 

[Mike722]

Re: Nav. and Brake lights Problem!

If you can try it on another vehicle or get one of those vehicle plug testers. That way you will know if it is the vehicle or the trailer causing problems.

A ford we owned had a seperate set of fuses for the trailer wiring. Vehicle lights worked but trailer brakes would blow at ramp if I forgot to unplug before launching.

I would bet that a fuse somewhere is bad from the touching wires.

 

[Splat]

Re: Nav. and Brake lights Problem!

Every GMC I've ever owned has a separate set of fuses under the hood for the trailer lighting.

BIll

 

[This_lil_fishy]

Re: Nav. and Brake lights Problem!

Any vehicle with a factory trailer harness will have a seperate fuse for the lights (and trailer brake controller if equipped). If it's an aftermarket set-up it'll be an inline fuse, or it'll blow the fuse for the lights on the vehicle itself.

Good luck, trailer wiring is very simple, but somehow extremely frustating to troubleshoot. One of those mysteries of life.


Ian

 

[Mark_VTfisherman]

Re: Nav. and Brake lights Problem!

If you can't find trailer fuses, how about a good old fashioned electrical meter? About $10. See if you have volts ahead of or behind the break, and at the splitter plugin or junction on the vehicle itself. Keeping checking forward until you find the issue.

Sometimes trailer lights don't work just because of corrosion or grounding issues... maybe there is a bad bulb or ground conincident with the wire problem.

Hope this helps.

 

[blchandler1981]

Re: Nav. and Brake lights Problem!

Checked under the hood of the truck and found two blown fuses. Now the park lights work on both sides, but the right brake and signal does not work. I replaced the tail lights and still no go. Does anyone have any suggestions? Thanks everyone, you guys have been very helpful.

 

[Mark_VTfisherman]

Re: Nav. and Brake lights Problem!

Do you have voltage at the bulb socket when the brake pedal is depressed?

 

[blchandler1981]

Re: Nav. and Brake lights Problem!

Sorry I'm new to this, but if understand you right your talking about any electric power in the tail light once I release the brakes. If so "yes"

 

[Mark_VTfisherman]

Re: Nav. and Brake lights Problem!

Sorry I'm new to this, but if understand you right your talking about any electric power in the tail light once I release the brakes. If so "yes"

Hey - no apologies needed!

Your trailer lights probably use an 1157 bulb, or if newer another dual filament bulb, maybe a 3xxx number bulb. I am making that assumption that your lights use a dual filament bulb: the tail lights (marker lights) in this situation use a smaller filament, and the brakes and directional use the larger filament. There is likely also a small 194-size bulb as the side marker light as well. But inside the rear-facing lens the bulb will have one filament for your marker lights, and the other is your brakes and directional indicator.

There will be no power to one of the contacts when the lights are on and the brake pedal is released (not depressed).

The question is not about there being power to the tail light when you release the brakes, but is there power at BOTH the contacts when the lights are on AND brake pedal is depressed.

If so, the bulb is either in the socket wrong or there is a contact or ground issue, or the bulb is defective.

If not, then you have to use the electric meter to work you way forward along the brake light wire until you find power, then go rearward again to find the break in the wire.

Hope this helps.