Tail/marker lights fuse?

[Rick Bjornholm]

My tail and marker lights are not coming on (2020 Heartland Mallard M301 travel trailer). Noticed that the lights went off as I was traveling down the road, Hit a bump and they went back on again and ran for several hours. Stopped. When starting again the lights failed to come back on. All other outside lights (stop/turn) work perfectly.
I checked and there is power at the truck 7 pin connector (pin 3) . At the front of the trailer at the junction box I have power to that point. Still no tail/marker lights. Question - is there a hidden fuse for the tail/marker lights located somewhere outside the 12v fuse panel for the inside 12v system? I looked at the wiring diagram and I do not see any fuse indication for that system. If not, I probably have a broken wire someplace inside the trailer which would be a bi... to locate.
Thanks.
Rick

 

[rhodies1]

Check the connections at the lights. The wiring runs back and it crimped at the light. Usually the wiring runs back on the right side and then across to the left light. It’s a start

 

[rhodies1]

Also make sure the connection in the junction box is connected properly. They use wire nuts to join the wires but you may have a loose connection in the wire nut.

 

[Rick Bjornholm]

Also make sure the connection in the junction box is connected properly. They use wire nuts to join the wires but you may have a loose connection in the wire nut.

Thanks, Rhodies1. Yes, I went to the junction box, applied 12v power to the green wire there (tail/running), still no lights. Quite frustrating. I see that on the left (drivers) side inside the storage area there is a removable panel at the front. I don't know what is behind there but it might be worth taking a look in there before bringing it to an RV repair station. Thanks for your suggestions and feedback.

 

[rhodies1]

Another trick you can try. At the rear tail light wire. Connect a piece of wire and run it up to the junction box at the front of your trailer unhook the tail light wire in the junction box from the pig tail wire coming from the truck. Take a meter and test to see if you have continuity in the trailer wire back to the light. If no continuity then you have a broken wire in the trailer somewhere.

 

[MDH2021]

Rick Bjornholm,

Check you ground wire for the light. If you have a voltmeter or test light open the light cover and remove the lamp, then test connections with your meter taking care not to short what should be the hot side of the lamp to ground.

 

[rhodies1]

Did you get this issue resolved.

 

[Torque Man]

As mentioned above, sounds like a bad ground connection.

 

[Rick Bjornholm]

I agree - it probably is a bad ground - but the puzzling thing is that directional and brake lights work. Guess they must have a separate ground. I have not had a chance to continue the search for the ground as we have had 2 days of rain with a promise of 5 more days of rain. I will post an update when I finally figure it out.

 

[rhodies1]

I would be very surprised if you had 2 separate ground wires.good luck in your search

 

[david-steph2018]

It could very well be rodent damage and the wire finally broke completely.

 

[Rick Bjornholm]

Final update. It turns out that it wasn't the trailer at all, it was my RAM 2500. For some reason there is no power for the tail lights at either the 4 pin or 7 pin connector on the truck (it helps if you test the correct pins). Tracking back I now find there is a special fuse for the trailer tail lights in the truck. It is a 30 amp block FMM MCASE type fuse. I will need to go to NAPA and get one. Guess they run about $6 each. I appreciate all the suggestions from all of you.

 

[Dahillbilly]

Final update. It turns out that it wasn't the trailer at all, it was my RAM 2500. For some reason there is no power for the tail lights at either the 4 pin or 7 pin connector on the truck (it helps if you test the correct pins). Tracking back I now find there is a special fuse for the trailer tail lights in the truck. It is a 30 amp block FMM MCASE type fuse. I will need to go to NAPA and get one. Guess they run about $6 each. I appreciate all the suggestions from all of you.

carry a spare just in case, I have a assortment of fuses I carry for both the RV & truck