Trailer Lights

KingFisher · 11-27-2016, 11:19 AM

Are driving me crazy. I had no problems with lights on any of my trailers until I traded trucks.
16 ft flatbed, hooked up and hauled my extra swingset to grand daughter's house to give it to her kids. No lights, but had brakes.

2012 Windjammer 3001W, hauled 30 miles to a different campground for work, had all lights except right running light and turn signal, had brakes, hauled it anyway. Then hooked the truck plug up to it to test later and all lights came on, but it was still hooked up to shore power and I didn't have the hitch connected. Not sure if I should have connected the truck light plug with shore power still connected, although I think I've done it before.

Hauled 2015 sunset trail 250RB to the dealer to have the front cap painted under warranty. No lights anywhere, but had brakes. Asked them to check when they moved it to see if they had lights, they didn't. Picked it up and brought it home after repair Friday, still no lights. But still have brakes.

Very confusing why I'd have all lights but one on one trailer and none on the others, and why I'd have brakes on all but no lights on 2.
I bought some contact cleaner and sprayed all the plugs yesterday, then scraped them with a nail file, and then sprayed again, including the truck.

Went from 2015 silverado 1500 to 2015 silverado 2500hd duramax so no difference in plug or wiring I wouldn't think.

KingFisher · 11-27-2016, 11:21 AM

I'll test the trailers before make my journey north to work today to see if it worked but I'm not optimistic.

WFD · 11-27-2016, 11:28 AM

Is your truck running when you plug into it? There was a thread going on here not long ago about guys having light issues with their Duramax trucks and some mentioned that the Duramax with all its electronics needs to be shut down before you plug into it. Maybe others on here that own them can elaborate on it, I just recall reading the thread.

uhduh camping · 11-27-2016, 12:58 PM

I would make a jumper wire. Put it in the 12V slot of trailer 7-way to use house battery then move it around to test the lights on the trailers themselves eliminating the truck from the equation. If all lights are working fine, then use a test light on truck 7-way to eliminate trailers to isolate the problem. But I think you would be looking for a bad ground contact.

herbike · 11-27-2016, 01:13 PM

I have a 2015 3500 that my son bought in June of 14. He was pulling a 52 ft car trailer with it and he had so much trouble with the trailer lights that GM finally had to put in a whole new wiring harness for the trailer plug. I've had this pickup since it had 69,000 miles on it and pulled our old fifth wheel and now a new bumper pull plus a homebuilt gooseneck with out any further light problems. The pu now has 103,000 miles on it.

KingFisher · 11-27-2016, 01:19 PM

I went out and checked. Plugged in with truck off. No lights on utility flat bed.

I got lights on sunset trail when I turned the lights on, no lights on the auto light setting, I'd think the running lights would come on on that setting but they don't. No flashers.

Going to check truck fuses before I leave for the north. Not pulling anything today, just trying to solve a problem.
I'll test the windjammer after I get up there, or sometime this week while I'm there.

KingFisher · 11-27-2016, 02:08 PM

Problem found in under hood fuse block. stop/turn left fuse blown, stop/turn right fuse blown, trailer back up fuse blown.

I assume running lights didn't come on before because I had the lights on automatic and it was daytime. When I checked the windjammer lights it was getting dark.

Now I have to find the reason for the blown fuses, possibly because of hooking up while still plugged in to shore power. Not sure.

**Bama Rambler** · 11-28-2016, 01:12 PM

The only thing running through the 7-way connector that could possibly be affected by hooking it up with the trailer on shore power, would be the charge line.

All the rest of the systems are completely separate. Running, stop/turn lights are not connected to the trailer battery and brakes would only be connected if the breakaway switch is pulled.

Hooking it up while on shore wouldn't have blown the stop/turn or backup fuses.

rockfordroo · 11-28-2016, 02:09 PM

Quote:

Originally Posted by KingFisher

Problem found in under hood fuse block. stop/turn left fuse blown, stop/turn right fuse blown, trailer back up fuse blown.

I assume running lights didn't come on before because I had the lights on automatic and it was daytime. When I checked the windjammer lights it was getting dark.

Now I have to find the reason for the blown fuses, possibly because of hooking up while still plugged in to shore power. Not sure.

You might want to get an adapter with LED's that you can plug into the truck, allowing you to eliminate the trailer; it's easier than messing with a test light or voltmeter (but not as cheap) at the 7 pin on the truck. I have this one to allow me to plug in my bike rack lights.

https://www.etrailer.com/Wiring/Hopkins/47345.html

The one above only gives you running lights and turn signals/brake lights.

This one's a bit more expensive, but would give you all the connections:

https://www.etrailer.com/Wiring/Pollak/PK12741.html

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