Anybody know why your brake lights would work when your headlights are off, but not when they are on?

Question

Anybody know why your brake lights would work when your headlights are off, but not work when the headlights are on, after you just replaced the fuse for the brake light?

Answer 1

many reasons why. first a bad headlight switch (they also turn on your running lights), bad ground on your tail light assemble----have you made sure that it's the brake lights and not the running lights. did you recheck the fuse. a short or open in your brake light switch, Was any other work done ?, is the tattle tail ground wire still going from the negative battery post to the car body-- it's not what you told us--it's what you have not told use is the key.

Answer 2

Bad ground wire, probably off the harness close to the tail-brake lights.

Answer 3

you have an electrical short mostly in the brake lights, since the barke lights run off the same bulbs as the headlight circuit

Answer 4

someone has probable put in a twin fillament bulb backwards or not listed all of it the way contained in the socket. So once you hit the brakes it makes contact with the different fringe of the bulb causing operating light fixtures to come back on.

Answer 5

if you are driving a 2000-2004 L-series Saturn there was a recall on the tail light assemblies about a year ago. Call the dealer and they should fix them for free.

Answer 6

Most likely you are driving a Chevrolet. Just kidding; you have an electrical short which may take a while to find. Maybe the switch for the lights.

Answer 7

you have a bad ground in the brake lights

Answer 8

you might have a bad alternator or battery. go to autozone or something and have them check it out.