HELP:TRAILER LIGHTS GO OUT WHEN BRAKE IS APPLIED

[mrjigger]

I have a problem with the lights on my trailer. Everything seems to be working, lights, turn signals. However when I apply the brakes the lights go out completely. Is this a grounding issue? I have the ground bonded directly to the trailer frame, but it seems a little rusty at the connection. I was going to try cleaning the connection next. Any other thoughts/solutions.

[Phred52]

It does sound like a ground issue. A good way to check is to run a jumper from the tow vehicle to the trailer frame. I've found that a battery jumper cable with the clamps on the ends works very well for this. Just clamp onto some clean frame metal on each end and check your lights. Phred52

[Macgyver55]

 Originally Posted By: mrjigger

Is this a grounding issue? I have the ground bonded directly to the trailer frame, but it seems a little rusty at the connection. I was going to try cleaning the connection next. Any other thoughts/solutions.

Yes it most definitely is! Make sure the ground terminal on the vehicle is indeed grounded and clean the groud you said is rusty. If it is a tilt trailer, see if it has a ground strap from the tongue to the bed. This is a spot that is often overlooked. If there isn't one, do yourself a favor and add one.

[Jeremy airjer W]

I'll third the ground! Its using the brake circuit to ground the running lights. As soon as the brakes are applied there is no where for the power to ground to and everything stops working!

[hoggs222]

I just went through this. I rewired my whole house and it still didn't work, so I did this: Take the ground on the back of the light and try grounding directly to the fish house frame. It worked.

[Sandmannd]

Another simple thing to check is the adaptor. My truck has the round plug and my trailers have the 4 pin so I have to use an adaptor. Changed my adaptor and it works great.

[Shack]

Good point Sand.

These trailer adapters (for some reason) have a split in them, that can corrode and cause issue.

[Jeremy airjer W]

 Originally Posted By: shackbash

These trailer adapters (for some reason) have a split in them, that can corrode and cause issue.

Haven't seen that yet but I have run into a bunch of wiring "T's" that corrode up. A little shot of our friend, die-electric grease, would save us from a lot of problems!!

Speaking of die-electric grease. I have the whole shop using it on belts. That was a great tip Shack!!

I should start an automotive tips and tricks thread, what do you think?

[Shack]

Ya, sounds like a great sticky.

Glad to hear you are using this. I have only worked at one dealer that knew of this, I have been spreading the word ever since.

On the adapter from a 7 pin to a 4 pin, for some reason the adapters I have owned are two pieces, with a split down the middle (never took it apart though). Instead of molding the outside case of the adapter as one continuous piece, they have it so you can separate the adapter for some reason (I think).

I noticed this in the past and after Sand brought it up, I figure I would throw in my 2 cents worth.

[Hookmaster]

Your using the die-electric grease as a belt dressing? What are the advantages? Any disadvantages?

[PierBridge]

 Originally Posted By: Hookmaster

Your using the die-electric grease as a belt dressing? What are the advantages? Any disadvantages?

Bump!

[Shack]

It was a Chrysler Service message from the mid to early nineties to apply die-electric grease to a belt to rule out a noisy tentioner verses a belt squeal, at least which is what I remember.

I have been using it for years to quit down noisy belts. It will not fix a "shot" belt, but on an after marker belt making noise, after a tech changes a water pump (or something) and gets coolant on the belt or just a plan noisy belt, it shuts that belt right up. As far as about 10 years of doing it, I have never seen an issue with applying it to belt.

Some belt dressing on the other hand can make a mess and make the noise louder.

Good luck

[Jeremy airjer W]

I'll second the belt dressing. This stuff is horrible and if I'm thinking clearly (which is rare) belt dressing is intended for v-belts not multi - rib or serpentine belts.

Advantages no squeaky belts and less come backs.

Disadvantages, less comebacks = less time to find other things things wrong with customers vehicles. Seriously I have not run into a problem and have only been experimenting with it for a few months.

I had my Tundra in for a belt noise TSB last fall. It was a fairly extensive repair. A new belt, tensioner, and A/C mounting bracket where installed. Sure enough it started making noise again the other day. Guess what I did tonight, You bet a little die electric grease and problem solved. We'll see how long it lasts!!

[Hookmaster]

Do you put it on the belt in a few places or a pulley and it spreads itself around?

[Jeremy airjer W]

Get a small detail brush with metal bristles. Apply a small amount of grease to the brush. With the engine running PLEASE USE EXTREME CAUTION DURING THIS PART - MOVING BELTS/ENGINE PARTS CAN CAUSE SEVERE INJURIES hold the brush up to the the belt, wherever this can easily be done, for a couple of seconds. If the belt was making noise it should quite up in this time

[Shack]

The brush way is the most effective, but if you want, another good way is (with engine off) dab a little of you finger and spread across back and ribbed side of belt. With the brush, you also want get both side. I tell ya, this idea does work very slick and last about 6-12 months, depending on you driving condition. Some belt may require a second application after a couple days.

Good luck…