2nd Gen Non-Engine/Transmission Help. No brake lights on trailer

[mikeg135]

I was told today by a good somaritan that I did not have any brake lights working on the trailer.



My brake lights are working on the truck.

I do have running lights on both truck and trailer.

I do have turn signals lights on both truck and trailer.

When trailer hooked up I have brakes lights on truck.



I did have a prodigy brake controller installed last fall. IT was installed wrong and it blew a brake fuse and turn signal fuse. But that was over 8 monthes ago. And everything has worked fine since.



When I do apply the brakes the running lights go out on the trailer and come back on as soon as I release the brake pedal.

Samething happens while using the turn signals.



Any suggestions?



Mike

 

[BV]

No Brake lights

95% of the problems I have seen are caused by bad grounds and corroded or weak connections.



If you have a test light and a second person you can easily check the trailer plug without the trailer hooked up and see it that part is okay.



If you can, try to operate the trailer brakes with the controller only just to verify if they are working. If they are not than you might still have a problem with the installation or again the grounding is bad.



Are you using the factory wiring?

 

[mikeg135]

Yes I am using the factory wiring.



Mike

 

[B.G. Smith]

Trailer lights

BV has nailed the problem, if the running lights go out when you hit the brake or turn signal then it is a bad ground. The ground is the #1 pin on the 7 wire connector, White I believe. It may not be the plug, check the ground wire where it connects to the trailer. bg

 

[mikeg135]

I will check all grounds tomorrow.



I was thinking is has to be the truck since it occurs on both of my trailers.



thanks for the input

Mike

 

[Matt42]

Originally posted by mikeg135

I will check all grounds tomorrow.



I was thinking is has to be the truck since it occurs on both of my trailers.



thanks for the input

Mike

If you have a factory towing package, you may have a trailer lighting relay. Part of it may be fried.

 

[PCrable]

Wiring Diagrams

Here's a link that shows the pinouts on the trailer plug so that you can use a tester and make sure you have all the pins on the trailer wired to the correct places. Hope it helps...



http://www.marksrv.com/wiring.htm



--Phil