[BillyinGA]

I had a short in my trailer. I had no brake or turn signals working on the trailer (only running lights worked). After fixing the trailer short, I discovered the BCM (Body Control Module), Trailer Tow fuse (#60 in the engine compartment relay box) was blown-15A. I replaced it and now the turn signal trailer lights work but no brake lights. I checked trailer tow fuses in the engine compartment fuse box number 1 (fuses 32 and 38) and the stop lamp relay, stop lamp switch in the passenger compartment fuse box (#20)with an ammeter. They checked fine. The turn and brake lights work fine on the truck with the trailer attached or unattached.
Have I missed a fuse? Any ideas what could be causing the trailer brake lights to not work?

I've tried to read the discussions on this subject but have not found and answer.

Thanks, Bill

 

[bngn4X]

could be an issue with your main harness. This is from a post not to long ago. see PDF

 

[BillyinGA]

Thank you for your response. I do not believe this will help me. I have the factory installed wiring harness. I have been towing a trailer since I bought the truck in 2013. No problems with the trailer lights until last week. Due to short in trailer I now have this problem. I do not believe your attachment helps me as it has worked fine before last week.
Thanks for replying. Bill

 

[bngn4X]

ah ok...sounds like it's isolated to your trailer then. any inline fuses on trailer? bulbs duel filament and maybe burnt out? all grounds on trailer if any look good ?

 

[vjmvjm]

Go to the connector plug on the back of the truck and check for power at the appropriate wire on the connector when you turn on the lights or apply the brakes. This will tell you whether the problem is in the truck or in the trailer.

 

[BillyinGA]

Thanks. No power to the brake light at the plug from the truck for the trailer. My guess is a blown fuse. But which one?

 

[bngn4X]

Check relays in wiring harness in passenger side kick panel ?

 

[erturne]

Thanks. No power to the brake light at the plug from the truck for the trailer. My guess is a blown fuse. But which one?

Check fuse #20 (10A). This may be in the interior fuse block; wiring diagram says "FUSE BLOCK (J/B)" which I think means Junction Box. Just a guess on the location, but that's the fuse for the stop lamp switch that goes through the electric brake wiring to the trailer receptacle.

 

[snippy106]

I had a short in my trailer. I had no brake or turn signals working on the trailer (only running lights worked). After fixing the trailer short, I discovered the BCM (Body Control Module), Trailer Tow fuse (#60 in the engine compartment relay box) was blown-15A. I replaced it and now the turn signal trailer lights work but no brake lights. I checked trailer tow fuses in the engine compartment fuse box number 1 (fuses 32 and 38) and the stop lamp relay, stop lamp switch in the passenger compartment fuse box (#20)with an ammeter. They checked fine. The turn and brake lights work fine on the truck with the trailer attached or unattached.
Have I missed a fuse? Any ideas what could be causing the trailer brake lights to not work?

I've tried to read the discussions on this subject but have not found and answer.

Thanks, Bill

I just bought a 2019 Crew cab sv with the hitch package. I hooked up my new boat and no lights. The plug went in and out easily so what I found was the pins were not making good contact. I took a screwdriver and bent the prongs on the truck plug. When I plugged the trailer in again everything worked.

 

[BillyinGA]

Thanks. I tested #20 (interior fuse box in the glove box). It was good. Still searching for answer.
Based upon other suggestions, I am wondering if it is a relay. Just not sure which one.

 

[Skibane]

I am wondering if it is a relay. Just not sure which one.

The brake relay should make a clicking sound every time you press on the brake pedal.

Use that to identify the relay.

 

[erturne]

The brake relay should make a clicking sound every time you press on the brake pedal.

Use that to identify the relay.

There's also a picture in the Factory Service Manual that shows where the relay is, in case the relay isn't working or isn't getting power.

 

[BillyinGA]

Thanks, I'll check the service manual.

 

[BillyinGA]

I continue to have a problem as discussed earlier. One solution I have seen is the two fuses under the steering column. I cannot find them. Is this used in newer Frontier's? Most mentions of this seem to be older versions. Any help will be helpful. Thanks.

 

[JTJD]

I have a very similar issue. Did you ever find a fix?

 

[houserco]

I have a very similar issue. Did you ever find a fix?

I also have a similar problem but I don't have the factory tow package. I just have a U-Haul install that someone did prior. Turn signals work on the trailer along with running lights... just not the brake lights. I've been to about four O-Reilly's and two AutoZones and no luck there. So far, all the fuses and relays I've checked seem good but I don't think I've hit them all.

Best of luck with yours!

 

[wjjones]

ah ok...sounds like it's isolated to your trailer then. any inline fuses on trailer? bulbs duel filament and maybe burnt out? all grounds on trailer if any look good ?

Actually no not the trailer it's at the truck side pigtail. I'm having the exact same issue. Running lights but no turn or brake lights. I hooked the trailer up to a co workers truck and the trailer lights all work fine.