I'm semi-new to the truck/trailer world, so forgive me if this is a simple fix. I have an '06 6.0 F-350 and regularly haul a horse trailer. The last time I hauled, when I plugged in the trailer, the lights did not come on. I had to get the trailer down the road so I drove it anyway. As soon as I started driving, the lights came on and then went off again and the dashboard said trailer disconnected. As I kept driving, the lights came back on and seemed to only disconnect when I braked or turned. At higher speeds (25+ mph) the lights stayed connected. My husband was following behind me in the SUV and said everything worked fine as long as we stayed a steady speed.

There is nothing wrong with the trailer part of the connection because I plugged it into my friends truck and it immediately connected. I've googled the problem and saw that it was probably a blown fuse; however, I couldn't find a solution for my specific model of truck.

Any info would be appreciated. The one Ford dealer around here is a complete rip-off and there aren't very many diesel mechanics around here, so if its an easy fix I'd rather not take it in.

 

Here's some labeled pictures of you fuse panel for future reference. I don't think that will be the problem though. I'd check the backside of the connector for mud/moisture and the trucks harness for damage. It's pretty common to snag them if you do any riding through weeds or small saplings. Welcome to FTE!


^^^----under hood fuse panel


^^^^----under dash fuse panel

 

If it was a blown fuse, it wouldn't work at all. It sounds like a bad connection. Are you using the big round plug...or a flat 3-4 wire trailer plug? The most common problem is a bad ground connection.

 

That's what I thought, but I can't explain why it would connect then disconnect. I'm using the big plug, it's a 7 way connector.

 

The first thing I would try is spray some electronic cleaner onto the metal contacts of your truck plug and the trailer plug. Then connect your trailer plug in and out of the truck plug several times.

This stuff is at Walmart & works good.

If you are still having problems, you will need to check the connector with a volt meter or test light.

Here is a diagram of your plug

 

Here ya go....watch this.

nothing to see here!

 

Thank you! I'll pick up the cleaner, volt meter, and test light tomorrow to try. Thanks again for the info!

 

The bulk of all trailer lighting problems is ground.If the trailer is not grounded thru the the plug you will have flashing lights due to bad contact thru the ball and chains.Clean your ground on the truck plug also.

 

Oh, I want to make dag gum clear...that ain't me in duh veedio. I fount it on duh innernets

 

One other place to check is the back side of the trailer plug on the truck side.
There is a small screw that holds the harness plug into the back of the socket.
Mine was not working and it turned out to be the green fuzz (corrosion) on the
back of the plug. Just pupped it out cleaned the harness end and put a new
plug assembly in it place and all is well. I have sense put some dielectric grease
in to prevent it in the future.

I think that you may find the same thing going on in your case.
Good luck and keep us posted.

Sean

 

It's most likely a dirty connection, but could also be a faulty trailer brake control. Mine recently did the same thing with saying the trailer was disconnected. It eventually gave me a TBC Fault code on the dash. It was repaired under my extended warranty. Something else to look into if simply cleaning it doesn't do the trick.

 

when I suspect ground problems I take a battery jumper cables and hook from the TR to the truck and drive it. If it fixes the problem, That should tell you if the ground is bad or you have to chase other problems

 

I think it has been well stated, I have 10 to 1 on the seven pin connection, even if it is the ground. If not on the side of the seven pin receptacle that you plug into, crawl underneath and work on the back side of the seven pin on the truck.

Steve

 

The place that fixed mine said that it was a common fault.

They did not charge me for the labor to test or R&R the plug.
I was having some other work done so it was while we are
there thing.

Sean

 

Excellent use of dielectric! Wish everyone would take the time to do that.

Steve