No running lights BUT wait, there’s MORE

Dadmedic683 · 08-04-2018, 11:33 AM

Recently we hooked up to travel to our latest get away. During my pre trip walk around, I noticed we didn’t have any functioning market lights. Brake lights and turn signals worked as well as the trailer brakes. All the trailer fuses in the truck are ok.

I had my neighbor come over with his truck to see if it was the camper or my truck. When he hooked his up the market lights came on the went off. So I figured it was a problem with my stuff.

Funny thing is now HIS camper has no marker lights. He has the same problem I have. His brake lights and turn signals work and his brakes are OK.

Ideas?

Please Help, there’s 2 campers not working now.

Reverse_snowbird · 08-04-2018, 12:10 PM

Were his lights working before he hooked up to your trailer?

Could it be that your rig caused a circuit breaker problem in both trucks?

I'm assuming that you've made sure the connection to the truck is solid. Occasionally we've had to 'wiggle' the connection to make the connection for all the lights. It wasn't in there firmly enough and not all the lights would light.

**Flybob** · 08-04-2018, 12:15 PM

Are you sure you are checking the trailer fuses in the TV? They are separate from TV signal fuses. There is usually one for each function.

RRGuy55 · 08-04-2018, 12:21 PM

I’ve been having the same problem - the fuse for the marker lights on my 2016 Sierra is in the fuse box under the hood with the larger fusable links, etc. Check your owners manual. Good luck!

Oaklevel · 08-04-2018, 12:25 PM

You are blowing the fuse in the tow vehicle(s). The fuses that you are checking are not the right ones. But that means there is a short in your trailer, the plug or a connection in a junction.

**Bama Rambler** · 08-04-2018, 12:27 PM

That 2015 Silverado has separate fuses for all the tow functions, so since it's blown two sets of TV fuses, sounds like your RV has a short in the running lights.

Those Chevy's have the tow fuses in a couple of different places. Most of the time they're in the underhood fuse box, but there was a few model years where they were in the opposite side of the dash from the standard fuse box.

Dadmedic683 · 08-04-2018, 03:32 PM

Quote:

Originally Posted by Reverse_snowbird

Were his lights working before he hooked up to your trailer?

Could it be that your rig caused a circuit breaker problem in both trucks?

I'm assuming that you've made sure the connection to the truck is solid. Occasionally we've had to 'wiggle' the connection to make the connection for all the lights. It wasn't in there firmly enough and not all the lights would light.

His lights were working before he hooked his truck up to my trailer.

Dadmedic683 · 08-04-2018, 03:33 PM

Quote:

Originally Posted by Bama Rambler

That 2015 Silverado has separate fuses for all the tow functions, so since it's blown two sets of TV fuses, sounds like your RV has a short in the running lights.

Those Chevy's have the tow fuses in a couple of different places. Most of the time they're in the underhood fuse box, but there was a few model years where they were in the opposite side of the dash from the standard fuse box.

We have the same year vehicle (his is a 2500 Sierra mine is a 1500 Silverado). We have checked the fuse box and all the trailer fuses are still intact.

Dadmedic683 · 08-04-2018, 03:35 PM

Quote:

Originally Posted by Oaklevel

You are blowing the fuse in the tow vehicle(s). The fuses that you are checking are not the right ones. But that means there is a short in your trailer, the plug or a connection in a junction.

So where are the correct fuses? Is there another fuse box? We have looked under the hood in the fuse box and all the trailer vehicle fuses are intact.

**Bama Rambler** · 08-04-2018, 03:48 PM

Did you test the fuses with a tester, or just look at them? There have been many times when a fuse looked good but turned out it was blown.

According to the internet (so it has to be right!

) the trailer parking lamp fuse is #15 in the underhood panel. Even if it looks good, I think I'd replace it and see what happens.

Dadmedic683 · 08-04-2018, 03:51 PM

Quote:

Originally Posted by Bama Rambler

Did you test the fuses with a tester, or just look at them? There have been many times when a fuse looked good but turned out it was blown.

According to the internet (so it has to be right!

) the trailer parking lamp fuse is #15 in the underhood panel. Even if it looks good, I think I'd replace it and see what happens.

We were looking at #15 (20amp).

Thanks, I’ll try it.

I agree internet never lies. 🤪

**Flybob** · 08-04-2018, 04:34 PM

My trailer light fuses are in s separate panel from the truck fuses.

Houston Remodeler · 08-04-2018, 05:18 PM

We ran into what I think is your problem;

We kept blowing the trailer running lights fuse which is located in the tow veehickle. We'd replace the fuse and everything would be great. Until we rode a few miles, then no more lights. If you're buddy's fuse blew, we know its the trailer.

It took me a while to figure out there was a short in the trailer wiring harness. Once home, I pulled the underbelly cover down and ran my hand along the wiring harness. At ONE point for ONE wire in the 4 wire harness, a single wire was bared as it passed over the metal frame of the trailer. This caused the short. I taped over the bared wired very well, and added a plastic shield over the frame. At the other points where the harness crossed the frame, I added cut pieces of plastic hose to act as a shield from the metal edges.

No more blown fuses after that. The new TT has plastic grommets every time the harness passes through metal.

MLBHSB · 08-04-2018, 05:30 PM

I'm gonna go out on a limb here, but did you look in the TV owners manual for the fuse locations?

rockfordroo · 08-04-2018, 05:49 PM

Trailer parking lights on my 2016 Silverado 2500HD are #15, as previously stated. Shown on page 401 of my owners manual.

Pull the fuse out and check with an ohm meter. Agree with others that somethings shorting out on your trailer.

Larry-NC · 08-05-2018, 02:36 PM

Open the driver's door. Pull the cap off the end of the dashboard. There are fuses there. More on the passenger side.

Larry

rockfordroo · 08-05-2018, 03:25 PM

Quote:

Originally Posted by Larry-NC

Open the driver's door. Pull the cap off the end of the dashboard. There are fuses there. More on the passenger side.

Larry

I've had two GM pickups. Neither had fuses in the ends of the dash.

hillsdaletc · 08-05-2018, 03:30 PM

The fuse (15amp) in the box feeds the trailer light relay. The relay is used to carry more current to the trailer for all the additional lights. Check your owners manual for the location of the “trailer light relay”on your truck. Check for power when lights are turned on at relay. Should be on two of the wires.

Larry-NC · 08-05-2018, 03:46 PM

[QUOTE=rockfordroo;1892220]I've had two GM pickups. Neither had fuses in the ends of the dash.[/QUOTE ]
Our 2006 Tahoe and our 2006 Yukon XL, both pic which are on the full-size pickup base, have the fuses there.

Larry

WY Husker Fan · 08-05-2018, 04:14 PM

To the OP - there is likely a diagram of the 7 pin plug on your truck right on the lid. If not the running lamps terminal is the upper left terminal with the key way on the top and the - or ground is the lower left terminal. Use a meter or a test light and probe those terminals with your vehicle running and the headlights on and you should have around 13.8 volts. If not then start looking for fuses. On my 2013 GMC Sierra there is a fuse marked “Trailer Park Lamps” in the underhood fuse block. I’m not sure about your truck but I would bet it’s similar. I had the same problem with a cargo trailer with an intermittent short that took me a while to track down and I would occasionally blow that fuse and loose the tail lights and marker lights. It’s likely the same thing happened to your neighbors truck when he plugged your trailer in.

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