Front Lights on Trailer Work But Rear Lights Dont Work and Get Hot

Published 07/16/2018

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Optronics Transit Tail Light - Brake and Tail Light - Incandescent - Surface Mount - Round - Red

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Question:

I should have clarified that my connection is a 7 way and this is a travel trailer. The front-running and side lights do come on. The back and back sides, do not. The wires are hot. When you say run down or track down the ground etc. Please be specific as I have no idea what you mean. How does one do this? How do you make the sure the ground it is good? When I look at the wires for my light, they are connected and look fine. Help! Thanks

asked by: Joyce

Helpful Expert Reply:

That definitely sounds like a ground issue. If your wires are hot and you are getting signals to the lights in front of them then you need to check your grounds. Not only do you have a main ground wire but each light itself will have a ground.

Check to make sure that your grounds are secure and connected to a clean, bare-metal surface. If those look good then the only other thing would be some damaged wiring. Check from the working lights to the lights that don't work and look for any places where it looks damaged or bent and replace accordingly.

Attached is a helpful article on troubleshooting wiring for you to check out as well.

expert reply by: Jon G

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Joyce

7/16/2018

Jon G.

7/16/2018

The ground wire on your trailer takes any "leftover" electricity and basically gets rid of it. Typically the ground wire is a white wire for electrical purposes. on your 7-Way it should be the wire in the 5 o'clock position (see attached photo) and will run to all (or most) of your electrical equipment on your travel trailer. Some trailer lights, like part # RVSTB61, actually have a wire that you connect to the main ground (that runs to your 7-Way). Other lights, like part # ST90RB, ground through the mounting hardware. When I mentioned checking your grounds I was referring to checking any wiring or hardware that would be used for a ground. If a ground is loose, damaged, or connected to a spot that has corrosion then it will cause backfeed and electrical problems like what you are experiencing. Look at all of your wiring and if that looks good check your trailer lights as well. If any of them do not have a wire that is connected to your ground circuit then it grounds through the mounting hardware and you need to make sure that looks good and is clean. If everything still looks good after you check it then you next best bet is to take it to a shop or have a friend who knows about wiring to take a look at it as a set of fresh eyes can help in situations like this.