After 20 minutes of driving, my car's headlights go out. Anyone know why?

Question

The headlight go out after 20 minutes, but the radio and clock have not been effected so I did not think it was the alternator.

The headlights may come back on as soon as I hit the brakes. The dash lights are also effected.

Thank you for your time.

Answer 1

i own a repair shop,and i think you have either a bad relay on it or the switch is heating up,and kicking out on it,they will do this ,and then when it cools off they,ll work again i repair a lot of them that are like this,and usually its the relay switch for them,but id have it checked real so,it can get hot enough to burn wires if the relay don't kick out on it so have it checked as soon as possible,i wish you luck with it,and hope this help,s.

Answer 2

I am not sure how old your car is, or what kind it is, but here is a couple of idea's 1st,,,,do you smell anything burning, even SLIGHTLY inside your car ??? maybe like plastic or rubber? If so; have your headlight switch checked; more so on Ford's...

If no problem there, then lets go to an updated system, if you have a car that has the headlight delay system, then go to your relay box, (location in Manual) go locate the relay, turn your lights on, and wait for the lights to go off...
When they go off, check the headlight relay by feel and see if it is hot or cold, by the way, (If you already carry a flashlight, fine, if not, get one) When changing relays or fuses always make sure light switch is off, and or Ignition switch is off, after repairing turnn power back on.
Now If the relay is cold; switch the head light relay with another relay (with the same numbers) (something that isn't important) in case the relay is bad...
Then see if the problem comes back, if not, you know the relay is bad. Some imports have a relay for each side, in that case, you will need a good Tech, or a(wire diagram of headlight system)and find; the loss of power,,,,,or loss of ground.
Sure hope this works for ya,
Curt

Answer 3

Headlights don’t have fuses, they function on a self resetting breaker. that's a protection function that forestalls a fire in you automobile at a similar time as maximizing the mild mandatory to correctly force to a secure place to provide up and have the issue fastened. once you have a “short” the electrical powered wires to the headlights are utilizing too lots electrical energy. If it maintains, the wires would desire to overheat and initiate a fire. The circuit breaker is interrupting the electrical powered energy to circumvent a fire yet shop resetting as quickly as there is time for the wires to relax back off. that's brought about by ability of a short (bare twine touching steel someplace) or a bad bulb, or consistent with hazard a bad circuit breaker. you should provide up driving once you like headlights and set up to get the issue regarded at and caught quickly. If the circuit breaker fails on the incorrect time you're able to be left with out mild in any respect, or worst case, you will locate your automobile on fire. Don’t force, get it fastened. Now!

Answer 4

you either got a bad light switch or a bad head light relay. look in the repair manual to locate the light relay and maybe change it

Answer 5

What is the name of the patient here Ford Chevy? How old is he or her? Let's help yamster mechanics out here year make model and some time how old?

Answer 6

Alternater is not maintaining the charge that is required to run them.It's the alt.

Answer 7

It would be most helpful to know what kind of vehicle we are working on.

Answer 8

That's very interesting, and sounds very dangerous. Beware of an electrical fire.

Answer 9

sounds like you got a short somewhere.

Answer 10

check your relays