trailer brake output

GlenS · April 29, 2017

So I towed my trailer this morning to a jobsite. I unhooked for a bit had some running around to do. Came back and hooked up. I have no output on trailer brakes. the gauge pops up on dash but no matter what I do I get no level indication. Checked fuses they seem ok. test for voltage i rear at plug with brakes on and no voltage. What am I missing. Trailer brake fuses under hood.///???

crankman · April 29, 2017

Glen does it say trailer connected when you plug it in your truck? All the light work?

HeliMark · April 29, 2017

So I towed my trailer this morning to a jobsite. I unhooked for a bit had some running around to do. Came back and hooked up. I have no output on trailer brakes. the gauge pops up on dash but no matter what I do I get no level indication. Checked fuses they seem ok. test for voltage i rear at plug with brakes on and no voltage. What am I missing. Trailer brake fuses under hood.///???

Unless the truck senses a trailer is actually hooked up, you will not get any brake voltage at the plug. I have had some issue's and usually cleaning the plug has fixed it. Or in a rush, plugging/unplugging several times works.

Mark

GlenS · April 30, 2017

Yes I have lights. I took it apart and cleaned it. Seems to be fine now . Out put is back. Wow it is a sensitive system. I understand what you are saying Mark. Thanks for the help guys.

Offcamber · April 30, 2017

This happened to me on my 1500... Usually just making sure the plug is all the way then you need to shut the truck down and restart. This should rest the system so the truck detects the trailer fully. You can get light and no brakes.

MotionMan · April 30, 2017

Dielectric grease. Jam the pins with it. Pack the flat 4 too, in MI with salt it will turn into green dust if you don't.

SouthpawHD · April 30, 2017

GM female plugs are known to have loose connections from time to time. On your trailer plug, pinch the trailer brake plugs closer together using a small pliers and you should be all set.

HeliMark · April 30, 2017

The plugs on the newer trucks seem to be a weak point. Clean and pack with the dielectric grease is a good suggestion no matter where you are located.

And wholly crap, do not pull the trailer emergency brake to test it when you are hooked up to the truck. Want to talk about sending the truck into an electrical tissy......

Mark

redwngr · April 30, 2017

Dielectric grease. Jam the pins with it. Pack the flat 4 too, in MI with salt it will turn into green dust if you don't.

The plugs on the newer trucks seem to be a weak point. Clean and pack with the dielectric grease is a good suggestion no matter where you are located.

And wholly crap, do not pull the trailer emergency brake to test it when you are hooked up to the truck. Want to talk about sending the truck into an electrical tissy......

Mark

You guys do realize that dielectric grease is non-conducting?

jpinoy · April 30, 2017

You guys do realize that dielectric grease is non-conducting?

I could be wrong, but I'm thinking they are meaning it for more of a protection of the contacts...

Or were you referring to the electrical tissy he talked about? I think that was just in reference to what he did to check the brakes.

"pull the trailer emergency brake to test it"

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Edited April 30, 2017 by jpinoy

HeliMark · May 1, 2017

The whole purpose of using dielectric grease is that it is non conductive. This is a simple way of protecting contacts from shorting out due to moisture in an enclosed environment. If the trailer plug on the truck didn't leak, one wouldn't have to do it.

The brake test was something completely different.

Mark

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4x4Pete · May 1, 2017

Dielectric grease has long been used for bulb connections even from the factory. Putting some dielectric grease on the trailer or any connection works to prevent corrosion but can get pretty messy. It works on any connection like battery cables too. It doesn't prevent conductivity of the connection (metal to metal) but prevents conductivity between different terminals and also keeps the air away which definitely helps with corrosion. Some greases can conduct electricity and cause a potential short circuit between terminals (like power and ground) without actual metal contact present.

Edited May 1, 2017 by 4x4Pete

Offcamber · May 1, 2017

If you use regular grease you run the risk of shorting out everything. Has to be Dielectric.

You guys do realize that dielectric grease is non-conducting?

You ave to use dielectric grease or you will short everything out....As stated keeps moisture out and contacts clean.

MotionMan · May 1, 2017

Yup, you can spread the grease around and not worry about arcing across terminals. It can get messy but if you don't go overboard you will be OK. It's helps the plug slide easier too so it does not pull the plug out of the bumper....which by the way is a poor design, you have to hold the male end so the female end does not rip it right out of the bumper plastic trim. But it is better than Ford where it is sideways and very close to the receiver pin.

Kmf294 · August 4, 2022

On 4/30/2017 at 10:42 AM, HeliMark said:

The plugs on the newer trucks seem to be a weak point. Clean and pack with the dielectric grease is a good suggestion no matter where you are located.

And wholly crap, do not pull the trailer emergency brake to test it when you are hooked up to the truck. Want to talk about sending the truck into an electrical tissy......

Mark

Any chance you can elaborate on that electrical tissy?