Left Brake/Turn Signal Out Help

[Kheth]

Hi all.

I have a 2009 X210-WBS and for the last 2 years it's been a peach. About 3 months ago, during a trip I get a call on the walkie-talkie (wife following) that my left brake light wasn't firing. At the next stop, I popped that light's cover - used my handy-dandy leatherman to scrape away some corrosion on the light's contacts - popped it back in and it worked just fine.

Then, during a recent trip the left tail light stopped working completely for braking and turn signalling ONLY - It fires just fine for the "running lights". We tried tracing the problem, but quickly found that the large wiring harness that comes from the TV disappears into the trailer from underneath and goes (God knows where). We've tested various bulbs, the ground at the tail-light itself and coming from the TV hooking.

I've read that sometimes these deals have their own fuse; but not being able to find the wires themselves it's impossible to trace, test along the way or check for a bad fuse.

- Does anyone know where such side-dependent fuses might be?
- Is there a fuse panel for voltage coming from the towing vehicle?
- Are there places to look for wires coming from the towing vehicle? I've searched the entire undercarriage and they're enclosed... somewhere.

Any suggestions are appreciated. Thanks

Cheers and happy trails..
Kheth

[profdant139]

We found that when the seven pin plug that sticks into the truck gets very dusty, the trailer lights become unreliable. I clean out the plug with compressed air. I tried dielectric grease, but I am not sure it helps much -- it could trap dust and grit, I think.

I sure hope that your problem is as easy as a dusty plug!

[Eagle]

This product works well to clean electrical contacts:

https://www.homedepot.com/p/CRC-11-o...5103/205021975

[vttimwhite]

The brake and turn signals for each side use the same wire. Always, always, always look at the simplest things first, like the trailer plug, bulb and the socket. Then, check to see if you have power at the VEHICLE side of the 7-way plug. The left turn signal is typically at the 9:00 position and the ground is at the 7:00 position on the plug (you can find diagrams all over the interwebs). If you have power there, you know it's a trailer problem. If not, it's a tow-vehicle problem.

My Silverado has different fuses for each side, but not my 2008 XT200, so if there's power at the tow vehicle, I suspect a wiring issue in the camper, most likely at a connector.

This is the part where a test light becomes your friend: There should be 3 wires entering the socket- white, yellow, and brown are the typical colors, but...

The white is ground, the yellow is turn/stop, and the brown is tail/running. Probably.

Turn on the left blinker.

Pierce the white wire with the probe if it's sharp enough, or a straight pin if not. Attach the black or ground lead from your test light to that white wire.

Then, pierce the yellow wire with the tip of the test light (or use a pin). The test light should blink. If it blinks, the problem is in your socket or bulb. If it doesn't blink, you can more or less assume that the bulb/socket combination is okay.

If the test light does not blink, and you're certain that you have power coming from the tow vehicle and that your 7-way is plugged in firmly and with clean connections, you likely have a broken wire somewhere. Visually inspect the wires and harness as far as you can see them. Look for cuts or too-sharp bends. Even a slight discoloration might be a clue.

Note: I typically dab a bit of silicone or Geocel in the holes I made in the wire to seal out water. Don't use electrical tape! That stuff make a mess and seals nothing. I often use liquid electrical tape with good results.

If you don't see anything suspicious in the harness, and you're not practiced in the dark art of electrical troubleshooting, you might be wise to take it to a competent dealer. If you want to try and find it yourself, you'll find out why I call it a "dark art". You're also likely to make up several brand-new cuss words as you bang your head and scrape your ears on the nether-regions of your travel trailer.

Good luck!

[Kheth]

I got it! Thanks all!!!

I decided to start at the back of my tow vehicle, grabbed a glow-meter and found out right away that the plug's left stop/turn blade was dead (right glowed like a champ). So suddenly, I had to apologize to my FF; having blamed him right off.

Turns out there was a blow fuse in the vehicle's integrated power module. I was surprised to find there was a specific fuse for "Lt Trailer-Tow Stop/Turn". I checked it and sure enough it was blown; replaced it.

I'm a little concerned with what made it blow in the first place; but if it does I'll know where to start.

Thanks again for your advice - you folks rock!

[profdant139]

Great news! In my truck's owner's manual, there is a chart showing the fuses and the locations. That's the good news. The bad news is that it is really hard to check the fuses -- they are in an awkward place. And even harder to pull them out.

Did you know that a poorly handled needle nose pliers can bust a perfectly good fuse?? I now know that for a fact.

[Kheth]

Originally Posted by profdant139

Great news! In my truck's owner's manual, there is a chart showing the fuses and the locations. That's the good news. The bad news is that it is really hard to check the fuses -- they are in an awkward place. And even harder to pull them out.

Did you know that a poorly handled needle nose pliers can bust a perfectly good fuse?? I now know that for a fact.

Funny... mine were very easy to access <knock on wood> and I *did* use needle nose plyers - though I know better. Thanks

[Eagle]

ALWAYS, The right tool for the job makes life easier:

https://www.ebay.com/itm/Pro-Car-Van...-/142680113510