Trailer lights don't work

SuperAllTerrain · January 2, 2020

I've got a 2016 CC LTZ short box and no matter what trailer I pull i have no drivers side turn signal or brake light. I even rewired my trailer (and my buddy hooked up his truck to it and it works fine) and have pulled my buddies boat( didn't work on mine). Still doesn't work. I am bringing it in to the dealership on Monday. But just was wondering if anyone else has had the same issue?

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Did you figure the problem I have the same issue

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SuperAllTerrain · January 2, 2020

I have a 16 Silverado with the same problem there are 2 relays in the circuit board that controls each side for the brake and turn signal under the fuse box that if the fuse don't blow it will burn the relay up I just changed the whole fuse box out cost me $232 and about 10 minutes and I got mine working again. Chevrolet has a bulletin out about using cheap fuses causing a lot of trouble. If I can help with pictures message me. Also my camper had a short I used a cheap fuse and that's what took mine out.

Yes please help out with pictures I’m having the same issue

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Michael04 · January 2, 2020

Easiest way to see if the relay is burnt out is to cut the switch on without starting your truck flip the turn signal to either left or right pop the hood and in the fuse block you should be able to hear the relay clicking if you don't that's more than likely your problem. If you look close above the 2 10 amp fuses the fuse for one of the turn signal is melted

Edited January 2, 2020 by Michael04

Mark Hensley · March 8, 2020

We were having the same issue. Turned the truck lights on manually and not on auto like one of the earlier posts said and it worked!

bububabo · June 10, 2020

Jimmyjam, did you ever figure the problem out?

I've got the same issue lately and I think it's the fuse too.

Pain in the butt though.

Hugrafix · March 31, 2021

I have a 2015 Silverado and bought a boat and the trailer lights werent working. I got the left blinker/brake working and found the issue was the ground, once I cleaned the mounting area the blinker and brake started working. This is where I made my mistake, as the blinker was still blinking I was getting all my other wires fastened, I touched one of the wires to the trailer and it shorted both the blinker and brake lights on the left side.

I bought all new lights and wiring as they were mismatched anyhow and rewired the trailer, when I tested still no blinker or brake on left side. After checking everything, I found out about the trailer FUSE which when I checked it was blown. I ordered fuses last night and replaced FUSE 14 which is for the trailer left turn and brake, tested again and no change, still no left turn or brake.

All lights on Right side work and running lights on left side. I also grounded to trailer with jumper cables just to make sure that was not the issue. What can I do next to get my issue resolved?

Tech Junky · April 26, 2021

Having the same issue on my 2017 Denali 2500HD. Tried turning the auto lights off and turning on manually but that didn't work. Currently only the right trailer turn signal does not work. Checked the fuse and it's good. Tested for voltage at the fuse and nothing. Turning on the left turn signal I can hear a click like a relay is being engaged and disengaged as the light blinks but do not hear that when the right signal is on. Thinking it's the 'engine compartment fuse block'. No signs of melting though. Thankfully I have an extended warranty and that is covered. Will post once I have it diagnosed and fixed. Will be a few weeks.

Ravenkeeper · April 27, 2021

4 hours ago, Tech Junky said:

Having the same issue on my 2017 Denali 2500HD. Tried turning the auto lights off and turning on manually but that didn't work. Currently only the right trailer turn signal does not work. Checked the fuse and it's good. Tested for voltage at the fuse and nothing. Turning on the left turn signal I can hear a click like a relay is being engaged and disengaged as the light blinks but do not hear that when the right signal is on. Thinking it's the 'engine compartment fuse block'. No signs of melting though. Thankfully I have an extended warranty and that is covered. Will post once I have it diagnosed and fixed. Will be a few weeks.

Have you metered out the receptacle on the truck? Or get a receptacle tester. If the receptacle works as advertised, then it's the trailer.

Thushanth · June 8, 2022

I am having the same issue. But when I connect with 4 pin it works fine. Just the 7 pin. Anyone know what this can be caused by?

paul Sufady · October 3, 2022

On 5/10/2019 at 9:32 AM, Michael04 said:

I have a 16 Silverado with the same problem there are 2 relays in the circuit board that controls each side for the brake and turn signal under the fuse box that if the fuse don't blow it will burn the relay up I just changed the whole fuse box out cost me $232 and about 10 minutes and I got mine working again. Chevrolet has a bulletin out about using cheap fuses causing a lot of trouble. If I can help with pictures message me. Also my camper had a short I used a cheap fuse and that's what took mine out.

SquattedChevOnBlack · January 13

On 4/26/2021 at 3:02 PM, Tech Junky said:

Having the same issue on my 2017 Denali 2500HD. Tried turning the auto lights off and turning on manually but that didn't work. Currently only the right trailer turn signal does not work. Checked the fuse and it's good. Tested for voltage at the fuse and nothing. Turning on the left turn signal I can hear a click like a relay is being engaged and disengaged as the light blinks but do not hear that when the right signal is on. Thinking it's the 'engine compartment fuse block'. No signs of melting though. Thankfully I have an extended warranty and that is covered. Will post once I have it diagnosed and fixed. Will be a few weeks.

*dies waiting for the warranty diagnosis and fix*