Okay, i preceed my problem with, yes i have searched and can't find an answer.

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2006 F150 Lariat using factory 4 pin
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I have blinkers, running lights, but no brake lights.

I checked all the fuses in the pass. kick panel and all good. Got my lead tester out and no light on the brown wire (4 pin). So i proceed to strip all the wire protector back to check the wire condition, no bends, kinks, and check the factory splice. All loked good. So i get the tester back out and check the wire connector above and behind the spare. I can't get a read on the brown wire, but can get one off the yellow and green.

All this was done with the break applied.

I guess my real question is how far back will i need to track this wire, or should i just take it to a dealer. Im mechanically and some what electrically adept, but im not going to trace and rewire my whole truck.

opinions please. I'm at a loss. Did i miss something?





pictures are of the wire connector above spare. You can see green and yellow wires 2nd and 3rd from bottom and brown with white stripe at top

 

Thought Blue was the brake line. Goes to pin 2 of the round 7pin connector (Bargman) to the trailer?

But that's for a 2011 ...

 

im using the 4 prong connector.

My trailer isnt wired for 7pin. Although i did buy a 7pin-->4prong adaptor and got the same issues

 

Brown should be running lights, yellow left, green right, white ground. Im having trouble myself with my running lights on our new trailer I just wired. Im going to have to do some wire testing.

 

Oops, sorry my bad.

If you've got left and right turns, the green& yellow wires are good. IIRC they're also used for the brake lights. Same bulb as the turns. What's wrong must be further up. Aftermarket, there's an adapter tacked in, usually at the taillights, that puts the brake signal to the green/yellow. Not sure where Ford does it. Probably up in the cab somewhere with all the other electrics.

 

Check the fuse under the hood?

 

It has already been said once, on US vehicles, the brakes are on the turn signal wires. European vehicles, brakes are a seperate wire.

If the trailer has no brakes lights, make sure you have everything grounded and all the grounds are bonded to the trailer at a clean/rust free spot. Many trailers ground through the ball. That often is a pretty poor ground, so make sure you have an actual ground wire from the light harness to the trailer frame.

 

If the ground is bad the turn signal will on the trailer will flash on with the truck flashes off, i.e. they'll be out of sync with one another. If you are having a ground problem you will not get brake lights as the light uses the brake circuit as ground. I am will to bet that if you turn on the blinker and then step on the brake you lose the turn signal...... And that is a bad trail ground. If for some reason it works, un-couple the trailer and just plug in the lights so there is no other trailer vehical contact and try it again, this will tell you if you have a bad trailer to truck grounding.