Help! Issue with No Interior or Exterior Lights on Trailer!

joebedford wrote:

wa8yxm wrote:
THIS. has nothing to do with running lights but it is also a safety issue because if tow vehicle and trailer part company.> The brakes on the trailer are engaged BY THAT SAME HOUSE BATTERY so check it out.

Having trouble understanding this post - are you quoting somebody?

Anyway, on my trailer, the TV powers the trailer brakes, not the trailer battery. The trailer battery powers the brakes only in case of a trailer runaway.

“Part company” = “runaway”

The trailer battery provides power to the brakes when the break-away switch is activated.

wa8yxm wrote:
THIS. has nothing to do with running lights but it is also a safety issue because if tow vehicle and trailer part company.> The brakes on the trailer are engaged BY THAT SAME HOUSE BATTERY so check it out.

Having trouble understanding this post - are you quoting somebody?

Anyway, on my trailer, the TV powers the trailer brakes, not the trailer battery. The trailer battery powers the brakes only in case of a trailer runaway.

I ended up going to a repair shop this morning. Most of the connections were in bad shape as was a fuse coming off of the battery, lots of grime. The real culprit was a ground wire under the trailer leading up into the electrical panel. The screw had rusted off and two large ground wires were dangling. I thought all of the grounds were up by the hitch. Thanks again for the suggestions.

Interior lights run on the house battery.. Which SHOULD be charged by pins 1 (Ground) and 4 (12 volt aux) on the 7 pin umbilical cable.

However not all Tow Vehicles are shipped with that lead enabled (Fuse or relay missing) and it is SUPPOSED to only provide power WHEN THE ENGINE IS RUNNING.

If the house battery is DEAD or Disconnected it will not light internal lights.

THIS. has nothing to do with running lights but it is also a safety issue because if tow vehicle and trailer part company.> The brakes on the trailer are engaged BY THAT SAME HOUSE BATTERY so check it out. (NOTE It may charge even if the disconnect is active (Disconnected) or not depending on disconnect. Brakes should bypass the disconnect but again, Some after market disconnects affect those as well.. next page Running lights

They work off the Tow Vehicle only, save for pin 1 (Ground) they have NOTHING in common with the interior lights.
Same for brake and turn lights.

Do the turn signals work?
What about brake lights?
Was the trailer connector on Travarse factory or after-market?

JVRVing wrote:
Hi all, it’s me who has the problem, Thanks for the help! The lights were going on and off while driving, so it is an interment problem, but when I pulled off the road it was more off than on.

While heading to FL last week, the running lights on our TT were intermittent. The brakes and brake lights were working fine however. The temperature was in the 20s and the cord was fairly stiff. Wiggling the cord while sitting still would cause the lights to go on/off. So that told me to look at the plug/socket for pin 3 (see Gordon-threes diagram). Bending the socket sides together at pin 3 (on the end of the cord to the trailer) with a small pocket screwdriver solved the problem.

Good luck......Hope this helps you.

Interior lights are a separate unrelated problem.

I feel for you! It's hard enough to find the single cause of a single problem. Multiple failures causing a single problem can be terrible to find. I think it's correct to believe that you have two separate problems (running lights, interior lights) that you happen to have noticed at the same time.
Wiggle tests are wonderful. Glad you're doing that.
You're also wise to pay the same attention to Ground as you do to Hot. All too often, we focus only on Hot. If the coach builder has driven ground screws into the coach body/frame, make sure they are neither 1. Loose (as in not driven far enough) 2. Stripped (need larger screw, different hole, replace with Nut and Bolt) 3. Driven but stopped before Screw Head actually binds the Ground Terminal to the Coach (can happen if the metal the screw is driven into, is thick enough to make the installer think a self tapping screw is tight but it hasn't bottomed to the head yet).
You need a Meter, maybe even a Test Light (which sometimes is better).
What's the Make/Model of this Trailer?

Hi all, it’s me who has the problem, Thanks for the help! The lights were going on and off while driving, so it is an interment problem, but when I pulled off the road it was more off than on. I check a few TV connections on the 7-pin with a light tester and they worked fine. I tried wiggling every ground connection I could find with no improvement. Joe417: Even though it looked fine, I started talking off the single ground screw for the battery and the TV ground, but couldn’t get it off due to the battery getting in the way. We decided to get to a RV Park for the night and noticed that while still flickering the lights were more on than off. I’m hoping that’s the problem and I can get a shorter screwdriver in the morning.

Every model camper is probably wired differently.

I took a look at how my camper is wired and can see that if the ground connection in the fuse box were open, it would disconnect ground to the running lights also. That would also cause any 12V device to fail, not just interior lights.

The ground bus can still be connected to the converter ground, so all 12V items would work if connected to shore power except running lights.

All my running and tail light grounds tie together and then run to the fuse box ground buss, while interior lights have two separate ground returns.

The battery, TV, and converter have separate ground wires to the buss. For both running lights and interior lights to fail at the same time would require that two wires fail at the same time.

Possible both the battery ground (probably a #6 AWG) and the TV ground (probably a #10 AWG) are under the same screw on the ground buss???? Pure speculation.