Hey guys. Got a weird problem. 02' 4.7 4x4 D.

The turn sigs, hazards, and running lights work. When the running lights are on the brake lights are on too. They don't go off at all. When the headlights are off then the brake lights turn off. No reaction or difference pressing the pedal.

A couple months ago the brake lights would come on only on one side and the third light wouldn't come on either. They just started working one day so I left em alone.

So, today I'm turning off the highway and almost got hamImered by a semi. Whew.

Any help would be appreciated. Thanks guys.

 

sounds like a short, probably between the wire for the rear brakes and the wire for the running(marker) lights

time to get an ohm meter out and start checking connections,

 

Could be a ground at the lights and check your bulb connections. Also check the trailer hitch connection if equipped.

I would also replace the brake light switch under the dash on top of the linkage, it is a 1/4 turn and lift up install.

Lastly it could be a bad CTM as the lights run through it, but that would be a last chance effort.

 

Ok I'll check all the above.

Da** it, I was hoping noone would say ctm.......

 

honestly the CTM is very unlikely IMO, a short is almost 100% the cause, just a matter or where, and the answer to that is usually the trailer wiring if equipped with it.