Brake/signal lights out

[mothernaturesson]

I've got a situation where I have tail lights but no brake/signal lights. Checked bulbs and fuses. Looking for suggestions what to check next. All the truck lights working fine. Could it be in the plug wiring or are there some fuses I'm missing?

[Siamese]

When I picked up my 2017 Jayco this Spring, one of the tail lights quit working on the trip home. I called the dealer, and they suggested checking the fuses in my tow vehicle. So, I got out the manual for my new Ford, and checked the fuses under the hood. They were fine.

I took the trailer back to the dealer, and they put in a new tail light. Didn't help.

They were thinking about putting in new wiring for the light, when one of the guys checked the ground on that side of the trailer. It was loose. Tightening it solved the problem.

The ground wire was under the trailer near the rear corner. Extended out of the covered under belly to the main frame of the trailer. The screw holding it to the main frame was the culprit. I've seen this reported by others on this forum.

Worth checking.

[Jagiven]

I'm not farmilar with the Tundra. Did yours come with a factory 7 pin wiring harness? If so, the tt has separate fuses for each function than the tv, so look in the fuse box, under the hood.

Personally I would use a multimeter at the 7 n pin, to verify you have signal at the connection. Also verify the connection points are not corroded.

From there you know to focus on the tt or the tv.

[Jay Dreamer]

x2 on the ground wire,, mine was about 12" from the back of the trailer....single wire coming down and screwed into the outside of the frame.

[Jagiven]

Originally Posted by Jay Dreamer

x2 on the ground wire,, mine was about 12" from the back of the trailer....single wire coming down and screwed into the outside of the frame.

I doubt it's a ground issue. If the ground was bad that light fixture would not light at all or would flicker.

[repacs0103]

Originally Posted by Jagiven

I doubt it's a ground issue. If the ground was bad that light fixture would not light at all or would flicker.

Agreed, a faulty ground would cause the tails to not work as well. Most modern trucks have separate fuses for left turn/stop and right turn/stop on the trailer. It's possible they are blown or that there's a connectivity problem elsewhere. As suggested, best place to start is with a test light or multimeter at the 7 pin connector so that you can isolate the problem to the truck or the trailer and work your way from there.


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[Origjcc]

Originally Posted by mothernaturesson

I've got a situation where I have tail lights but no brake/signal lights. Checked bulbs and fuses. Looking for suggestions what to check next. All the truck lights working fine. Could it be in the plug wiring or are there some fuses I'm missing?

Id check the trucks fuse's, most manufactures have separate fuse for tow plugs. Run through in cabin and under hood with a test light. My two cents.


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[Scott91370]

Take the trailer side of the plug and hook your 12v battery directly to the negative and the correct prong for the lights that are not working. If it works it's the truck, if not it's the trailer.

[mothernaturesson]

Thanks for the suggestions. The trucks a 2001 and plug was installed by dealer would it still have separate fuses I wonder? I'll definitely give these a try.

[Jagiven]

Originally Posted by mothernaturesson

Thanks for the suggestions. The trucks a 2001 and plug was installed by dealer would it still have separate fuses I wonder? I'll definitely give these a try.

Most likely Not. often they just splice into the lights at the rear of the vehicle, and run a new brake and AUX line. However, I have seen some manufactures (I'm not familiar with Toyota) run the wire harness down, and not us the plug and it is just stuffed up into the chassis somewhere. So there is a chance it is a factory wire harness, with a 7 pin plug just added, and a brake controller added.

You can buy a "trailer wire tester". This will check the signal up to the hitch on the TV side. This tool is fairly cheap. Does the same thing as a multi-meter, just a dedicated tool for a single use.

On my canoe trailer the wire harness give me grief all the time. I have used the technique Scott97310 mentioned in another post. I used my portable battery jumper, to test the lights. connected a wire from the Ground pin to the black jumper cable, and then used another wire from the red jumper cable to test the various lights. It is a little Jerry Rigged, but it works, and keeps the TV wire harness out of the loop.

[etex211]

The tail lights they put on these campers are very cheaply made. The sockets and bulbs get rusty very quickly.

The LED conversion kit I got for mine was about 40 bucks, and it will hopefully solve my tail light problem by eliminating the bulb/socket connection.

[Dizz]

Originally Posted by mothernaturesson

I've got a situation where I have tail lights but no brake/signal lights. Checked bulbs and fuses. Looking for suggestions what to check next. All the truck lights working fine. Could it be in the plug wiring or are there some fuses I'm missing?

I had same problem,connection near the lights was corroded.. dealer cut wires and recrimped connection with electrical grease,works fine..