Troubleshooting Intermittent Trailer Disconnected Message When Towing

Question:

I’m getting intermittent trailer disconnected messages when towing my toy hauler. My other trailers do not have the same problem. Looking at the trailer brake wiring, it appears the brakes are pulling ground directly from the tow vehicle through the 7 pin connector. Is this ok? I have three axels and all Of the brake wire connectors are non-water proof. I guess a lot of areas where the problem could be. Any literature on how To go about narrowing the problem Before i pull the hubs and look at the magnets Bill ?

asked by: Bill

Expert Reply:

Hey Bill thanks for your question. Like you said there are several things that can cause an intermittent trailer disconnected message. The most common cause is a rusty or corroded trailer connector. Go ahead and inspect the trailers 7-way plug. If there is noticeable rust or corrosion it will need to be replaced with something like the 7-Way Round RV Style Trailer Connector # A7WCB. I suggest using a bit of Dielectric Grease # 11755 on the trailer plug and the vehicles 7-way.

It is ok for the brakes to be pulling ground from the trailer connector, so that sounds normal. Intermittent signal can be caused by a bad ground though, which could point to the brake wiring or the trailer connector itself.

If the connections are not waterproofed that could also be causing issues since there might be corrosion on some of the connections. You will want to thoroughly inspect all of the wiring connections on the trailer. Keep an eye out for any loose connections or frayed wire. I suggest using heat shrink connectors such as part # DW05745-10, which will help waterproof your connections.

I am not sure exactly what kind of trailer you have or how old it is, but I would certainly check the trailer plug and wiring before removing the hubs and such. It might end up being a simple fix.

I have linked a bit of literature below which you may find helpful, especially the article on how to test your brake magnets. You can feel free to let me know if you have further questions.