Tail lights

Catherine and Don · 09-04-2022, 04:36 PM

The tail lights on our 5th wheel have quit working. All the other lights work, brake lights and turn signals are fine. Has anyone else had this problem?

**JFlightRisk** · 09-04-2022, 06:09 PM

Are your taillights LED or incandescent bulbs?

Catherine and Don · 09-04-2022, 06:22 PM

LED on our 2017 28.5rsts

**JFlightRisk** · 09-04-2022, 08:31 PM

I'd start with any fuses related to trailer towing, then check the connections on the 7-pin plug and socket. After those test ok, the 5th wheel's wiring junction box. A digital volt/ohm meter or a 12-volt test light is going to be necessary. The grounds are ok since the brake and turn signals work. Those two are on the same circuit, and the taillights are on another.

Catherine and Don · 09-04-2022, 11:35 PM

Thank you. We'll give that a try.

Marcm157 · 09-05-2022, 07:11 AM

What are you towing with? Many tow vehicles have separate fuses for trailer lighting functions. You can isolate the problem by sending 12 volts directly down the trailer connector on the 5th wheel. You can activate each function individually. If all the lights work that way the problem would be in the truck.

Catherine and Don · 09-05-2022, 08:25 AM

We are towing with a 2019 F350. We checked the fuses related to towing and they are fine. We were hoping for an easy fix since we are in the middle of a trip but that doesn't seem to be the case.

Marcm157 · 09-05-2022, 08:51 AM

Did you check the fuses in the engine compartment by the passenger side fender close to the firewall? That's where I found a fuse that controlled my marker lights. The Ford o. wners manual wasn't very clear and I found fuses in multiple locations.

NCRetired · 09-06-2022, 06:56 AM

Make sure that you don’t have the light switch in truck set to automatic on/off. You will need to insure that the headlight switch is actually on and you the headlights are on on the truck. I’ve made this mistake more than once.

Jerry713 · 09-06-2022, 08:48 AM

Sounds like a ground issue. I would start at the lights and check the ground wire there then follow the ground best you can to the front of the trailer.

Plug in the lights to the tow vehicle and use a voltage meter to determine whether you have 12 volt power to the wiring at the tail lights. If not you have a break somewhere between the lights and the tow vehicle.

Catherine and Don · 09-06-2022, 09:19 AM

Lol. That's the first thing I asked my hubby to check. It was in the correct position. Thank you.

Catherine and Don · 09-06-2022, 09:20 AM

We did. Thank you.

Dqx2 · 09-21-2022, 02:52 PM

No one has mentioned this from what I can see, but make sure the taillights are not full of water. It can be hard to pick up, particularly if full. I have seen this more than once on LED taillights, once for me, once for my sone on his Cougar. Sometimes the seals dry out and let water in.

Catherine and Don · 09-21-2022, 03:34 PM

Thank you. We still haven't figured it out so we will check that.

Catherine and Don · 09-26-2022, 10:02 PM

Thank you to everyone who gave us ideas on our tail light problem. My husband and son found a short in a wire, fixed it, and we are good to go. We also found that a couple of our side lights had water leaks because they weren't mounted correctly. Those are getting replaced because of rust and some of the led's shorting out. We will mount them correctly AND seal them.

Thanks again everyone. You guys rock!

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