Why would brake lights only come on with headlights on?

Question

I have a 2003 Grand Cherokee, and recently the brake lights will only come on with headlights on. And they stay on all the time. Otherwise nada... help!

Answer 1

They're probably not your brake lights; They are your parking or "running" lights which are wires to come on when you turn on on the headlights. To see if your brake lights are working, get a friend to stand behind you vehicle while you step on the brake pedal. No light ? Check the fuse first, then the bulbs, then the recepticals for corrosion. Still no light ? Check the wiring with a test light.  

Answer 2

LOL I thought this only happened to me!  Your wires are crossed somewheres...a mechanic can find it quickly and it should not cost very much.