Headlights keep burning out

[CRUZIN66]

I need some help. Yesterday I was driving home from work and both of my headlights went out. I checked the connections and they all looked good. I tested the headlight plugs and I had power to the headlights. I replaced the headlights and they work fine. Today when I turned them on coming home from work they both blew out again. Any suggestions?

 

[Viperwolf1]

What's the voltage at the plugs with the engine running?

 

[70_Steve]

There is a thermal reset circuit breaker in the headlamp switch. On overcurrent it will break the headlamp circuit, and the headlights go out. After a few minutes it will reset.

Did you verify that the old headlights were indeed bad, or did you just replace them, see the new ones worked, and assume the old ones were bad? Those thermal circuit breakers do go bad, and will open the circuit with normal headlight current. The fix is to replace the headlight switch.

 

[av bronco]

The thermal switch will do that and-or you could be overcharging.

 

[broncnaz]

Might also want to check the wiring to the dimmer switch many times it gets bad and causes the headlight switch to act up.

 

[blubuckaroo]

Like Broncas said, The dimmer can be a real problem on these. The switch and terminals can be really corroded. It is in the same environment as a rusted out floorboard.

 

[CRUZIN66]

I replaced the headlight switch the high beam switch and the alternator last month. The tail lights and dimmer still work, everything except for the headlights. After the old ones blew out i replaced them with new ones and the same thing happened. Could it be a bad voltage regulator? and the headlights are getting too much juice? Im going to check the voltage at the plug with the engine running like someone suggested and let you know.

 

[vintage bronco]

check for bad grounds i do not know where they are located but i am sure someone will chime in. bad grounds will blow bulbs quick.

 

[Pa PITT]

Surely check you voltage but I'M with one of the 1st responders get one of the old bulbs and put a jumper to it from the battery and see if it lights up .. I'LL BET either your dimmer switch or headlamp switch is bad .. Also check your grounds but when I've lost ground to head lamps I've had yellow lights.

 

[DirtDonk]

Unfortunately, he's already replaced both the switches and alternator.
So back to wiring and regulators I guess. See what the alternator is putting out when running, but if it's putting out enough to blow headlights, I'd think it'd be enough to blow tail lights too.
Not to mention the high-beams when you click them on to check things.

Paul