Electrical issue: apply brakes dims dash lights

When I apply the brakes, my dash lights dim and my front / upper marker lights illuminate.

Other info:
:: Only happens when lights are off, everything acts normally when lights are on.
:: Brake lights work.
:: I think my cruise control is wonky too.
:: It's all stock. I don't have any aftermarket lighting
:: 2007 v6 pre-runner / 62000 miles

I did a search and found someone with similar issues talking about a "Curt harness" but I don't have that. Is that some kind of aftermarket trailer harness? My truck has the stock tow package and lighting.

Any help / advice would be appreciated!

 

You have a bad brake light. If you don't want to try and figure out which one just replace both of them. I had a similar problem on a car with the right turn signal flashing the marker lights. I hope this solves your problem.

 

Try unplugging one tail light assembly at a time to see if the issue goes away - to help isolate the above theory - if it doesn't, check for damage or corrosion at the trailer electrical socket. A bad bulb, bad tail / brake light ground circuit, of a short circuit in the tail light or trailer wiring could be possibilities.

And yes, Curt is an aftermarket supplier of towing harnesses, hitches, and accessories - doesn't sound like you need to worry about that.

 

By the way I was talking about replacing the bulbs not the whole taillight assembly.

 

Yeah, I understood as much, good you clarified for OP.

 

Thanks for the responses guys - I will have a look tonight and let you know how it goes.

 

I took the tail light off - and the tail / brake light bulb was rattling around in there. Took it out and plugged it back in and all is back to normal!

Man, it was really a bee itch to get the bulb out of there. It was rattling around loose, but positioned just right so it wouldn't fall out and I could not grab it with my fingers. Used a forceps and coaxed it out.

Also, you guys are gonna think I’m nuts, but the cruise control stopped working then too. what. the. firetruck. A mechanic friend of mine said, "Cruise controls feed off the rear brake light circuit . They need to see the resistance and unburnt bulb."
The more ya know...

Case closed, thanks guys.