trailer turn signals, and brake lights

[shocker2008]

I hooked up my enclosed trailer today and all the lights work except the right and left turn signal and the brake lights. I am wondering what to check, I saw in the owners manual that there are 2 relays under the hood for these functions. What are the chances that both relays are bad? Or is there anything else to check?

[ol38y]

I'd check your trailer wires

[shocker2008]

I checked that right away on another truck, the problem exists in my truck? Any thoughts?

[mbahr22250]

You using a flat 4 plug or the round 7 plug? The Ford plug-in's for the flat plugs are notorious for being really crappy. I replaced about 4 of them on my last truck and I only use the round one on my current truck. The adapters from flat to round are about $20.

[shocker2008]

It's in the 7 pin connector.

[SuperCrutyPS]

Does your manual show any fuses under the hood for those circuits? My '01 has fuses under the hood....but things may have changed since then.

[shocker2008]

No fuses, two relays

[mbahr22250]

Pull the harness apart at the plug-in underneath the truck where the harness for the trailer plug plug's into the main harness for the back of the truck, use a test light and see if there's power for everything there.

[mor4wd]

It's also possible that the truck you tested the trailer on is wired to work with that trailer. I would check the actual wiring configuration on the trailer harness. If it's older it may have come wired differently, or somebody switched the pins so that it would work with their truck.

[ol38y]

Originally Posted by mor4wd

It's also possible that the truck you tested the trailer on is wired to work with that trailer. I would check the actual wiring configuration on the trailer harness. If it's older it may have come wired differently, or somebody switched the pins so that it would work with their truck.

Good point. Check your socket on the back of the truck. See if you have turn signals at the back of your truck.