Left Tail Light Issues

[Trailguy]

Hey everyone,

My left tail light is having some issues. I have running lights, but the turn signal and brake light isn’t working.

Assuming it’s a bulb, I’m not sure how to get the cover off. It is mounted with 4 screws (easy enough), but also appears to be sealed to the camper with some kind of white sealant, which is apparent after removing the screws. I could try and pry it off, but the sealant has high adhesion and I don’t want to break anything. Just curious if you guys have run into this?

I have read many posts on the tail lights, and as far as checking voltage and such/ cleaning the connector with contact fluid/ wiring, etc., I can always go that route too if necessary. Light is pictured below. I don’t see a way to pop the red lens off either. I think I remember boats being sealed this way, still yet, I’ve never had to take one off yet.

 

[Bill]

With some care, the red lens should pop right off the base, exposing the bulbs - or, if LEDs, at least showing how to access them. It generally involves squeezing and gently prying the lens at the middle of each long side, or occasionally at the ends. Is there really any need to get access to the wires and connectors? There may be - but try the bulb replacement first.

 

[Trailguy]

Thanks Bill. I’ll let you know how it goes.

 

[Bill]

Do you have any kind of a 12-volt test light? Or maybe a voltmeter or DVM? If you get into wiring and bulb-checking, you will find it very handy, and a big time-saver. Available cheap (meaning $5-$10) at any hardware store or big box store.

 

[Trailguy]

I do have a volt tester. I’m sure I’ll use it at some point with this TM. I haven’t worked on the bulbs yet, but I’ll definitely let you know if I was successful or not. Hopefully just a bulb. Speaking of wiring, what kind of insulation do you guys use when the big cables that run along the trailer start to crack? I thought that shrink tubing might be an option, but kind of a pain, that’ll turn into a project. High grade electrical tape is an option. Might not look the prettiest lol.

 

[Bill]

For mechanical protection of long wires or cables, electrical tape is not the best choice, since it tends to dry out and unwrap. Split loom is good since it provides mechanical protection, and you can slip it over a wire without disconnecting one end. Heat shrink is not quite as good for long runs, as it is kinda stiff and tends to crack when flexed repeatedly. And you need to disconnect one end of the wire to slip it into the tube.

If you need actual insulation (rather than mechanical protection) of short bare wires or connectors, the best choice probably shrink tubing as you mentioned. Or try "self-fusing electrical tape". You'll find this in the same display as ordinary electrical tape, but in my experience, the counter jockeys have never heard of it.

 

[Trailguy]

Thanks Bill. I’ll check out the split loom, and I’ll let you know how the light fix went.

 

[Trailguy]

Hey Bill, turns out the light issue was not the trailer, but the tow vehicle. My father in law added trailer brake wiring, so I’m wondering if his after market addition is the issue. I’ll have to trace back what he did and find out why the left side brake light and turn signal isn’t working. The male connector on the vehicle looks great and clean, so I imagine it’s a wire issue somewhere.

 

[Kidkraz]

Bought this for my nephew, but figured I'd toss it out there. Amzn sells this for under $20.

7-Way RV Blade Connector Tester

Part of towing responsibly is making sure your trailer lights are working properly. Whether you have just installed a new custom wiring harness or are trying to locate the cause of an electrical problem, CURT connector testers are great for testing tail lights, turn signals, brake lights, ground...

www.curtmfg.com

 

[Bill]

That's a great item! It could save hours of looking for a problem in the wrong location (tow vehicle vs TM).

 

[Bill]

TrailGuy posted "I’ll have to ... find out why the left side brake light and turn signal isn’t working." As you have probably discovered, on each side of the rig, the turn-and-brake light is a single light powered over a single wire. The problem may be as simple as a wire not making contact somewhere along the line.

Tail light problems are often caused by bad grounds, but I don't think that is the issue here. I believe this is a dual filament bulb, the other filament in that bulb being the running light (tail light). If that other filament lights up properly, that eliminates a ground issue. Have you confirmed that both filaments are good?

Good hunting.

 

[Trailguy]

I did not. I have two trailers, the TM and a utility trailer. I have the same issue with both trailers on my Traverse. Confirmed by using other vehicles plugged into the trailers. I would have never thought it was the vehicle side.

 

[Bill]

Good trouble-shooting! Let us know the answer as you uncover it.

 

[Shane826]

Those testers are great until you get into some of the *ahem* "smart" vehicles in recent years that look for a load on the brake circuit before activating the light circuits. Seems a little overkill to me, but I'm sure saving that electrical load on the alternator gained them 0.0001mpg so I guess it's worth it?

 

[Trailguy]

Well friends, turns out it was the 10 amp micro fuse in the Traverse fuse box. Each circuit has a fuse, this one was for the left stop/turn signal.

Now to figure out why it was blown….for another day!