I have a 2002 Dodge Durango slt 4.7.
The problem I'm having started a few years ago, I'm blaming a bear.. anyways.
My brake lights havent worked in a long time, except for the center back window light, it works fine. Ive replaced bulbs and fuses. The tricky part is, if I hook up a trailer all the lights work great.
Seeings how I dont want to pull a trailer everywhere I go, does anyone have thoughts on why my brakes only work when I'm hooked up?
The bear blaming... camping one year I had a bear come visit, as he was bumping my Durango (used as my tent, Im safe), he climbed into the back of my friends truck and dumped out the ice chest full of beer (heres the sign to stop drinking), then proceeded towards the tents. I hit panic button thinking the noise and lights would scare him off. Nope. So I slammed on the horn, bear looked at me like is was nuts and still didnt leave... BUT... Entire Durango went out, no power, no lights, wont start, nothing except the dinger saying my keys are in ignition wouldnt stop beeping, I was holding my keys. We disconnected battery, everything went back to normal except my brake lights. See its the bears fault. He did leave a little while later but his mamma had to come get him.

 

Have you checked the sockets to see if they are bad? Move the "backup light" socket to the brake light position and check.

Do you have dash lights?

Have you checked the stop lamp fuse in the fuse box under the hood?

 

I wonder if you might have a ground issue since they work with a trailer connected.

 

I've replaced all fuses under dash and under hood, I've replaced bulbs and switched sockets around. I have all dash lights, reverse lights, blinkers, hazards etc... I had someone else suggest a ground issue in trailer connectors, gonna try replacing that and see what happens.
Any other thoughts for me to try in case that doesn't work would be fantastic.

 

i would take and check the grounds for the tail lights see if they got dislodged somehow, it sounds like the trailer circuit is completing the circuit which to me means that there is no ground connection for the brake lights w/o the trailer hooked up