[paniolo]

OK, picked up a new trailer today. Hooked it up to my 81 Chevy Sub. that has been wired up for awhile. Went through all the output pins and matched them up with corresponding trailer pins but still can't get it to work. When I have the running lights on and hit the brakes all the lights on the trailer go out. When I hit the turn signals the lights work OK, but my brake controller flashes on and off and I can feel the brakes engaging. I double checked the brake engage line and it is hooked up correctly. Hooked the trailer up to a buddys rig and it all worked right. I've had several trailers behind my rig before and everything worked good too. What you think...something on the vehicle harness shorting out?? Or could it be the trialer ground?

Help, I'm trying to make a trip this weekend.

 

[EMIEVEL]

It sounds like a ground to me. My trailer lights do not work correctly UNTIL I drive forward and put some pull force against the hitch. Sounds wierd I know, but did you drive with it yet? Otherwise, ground the truck to the hitch ball and see what happens.

 

[paniolo]

Yeah, I thought it was ground too... checked with ohm meter and it was grounding. BUT after driving it home they are working fine now so it had to have been the ground. I'm going to run a separate ground wire from the trailer frame... I've already got a ground with a male pin wired off my trailer hitch.

 

[FYRMAN]

It sounds like a ground to me. My trailer lights do not work correctly UNTIL I drive forward and put some pull force against the hitch. Sounds wierd I know, but did you drive with it yet? Otherwise, ground the truck to the hitch ball and see what happens.

The trailer is grounding through the trailer ball. You need to splice into the ground wire and just run a new ground.







paniolo, are you sure that you have all of the pins going to the right spots? Look inside the plug again and make sure there are no little strands of wire touching the other terminals. All it takes is one little hair to fuck it all up.

Also, make sure your lights are grounded and not just back feeding through the other lights. This is what it sounds like to me.

 

[70~K5]

When I pulled double semi trailers for a living, they didn't always have a good ground. This would make the marker lights etc. flash with the turn signals. What my friends and I would do is carry a 15' 14 gauge wire with large clips on both ends to ground the front traile to the back one. This was a quick easy trick to fix the problem. If you make up something like this it has many uses in your tool box and makes it easy to check a bad ground too.

 

[FYRMAN]

When I pulled double semi trailers for a living, they

Agreed

 

[paniolo]

thinking about it, I tested the vehicle ground through the plug but didn't actually double check that the trailer ground was truly grounding...I bet thats it. That 14 ga wire trick sounds like a good tool box item too...Thanks

 

[70~K5]

Yep and it helps when you need to test something out. I used it yesterday with an extra battery for my boat to check the motor in the back hatch of a '73 Blazer.

 

[EMIEVEL]

What I was getting at was if the trailer is trying to ground through the ball, it might not ground until the hitch moves around a bit (from towing). Most hitch recievers are painted or rusted and might not ground well until that slop in the reciever gets jarred. Does that make any sense?
What I don't understand is, I run a ground from a light to the trailer frame. Then I run a ground wire from the frame into the plug, that connects to the truck ground wire. So why does my trailer not ground until I move? It shouldn't matter what the hitch is doing.

 

[70~K5]

What I don't understand is, I run a ground from a light to the trailer frame. Then I run a ground wire from the frame into the plug, that connects to the truck ground wire. So why does my trailer not ground until I move? It shouldn't matter what the hitch is doing.

If you're sure of the trailer ground, then check the one from the trailer plug on the truck. Do you have a star washer where it ataches to the truck frame? On the trailer do you have star washers where they hook to the frame? Those little washers make alot of difference if not used.