blinking headlights

[natec73]

gentlemen, i need help. my headlights are flashing and i can't figure it out.
details: 74 Bronco 302. after about 5 minutes of driving at night, my headlights will begin to blink on and off: both low beams and high beams. the key to remember, is that it ONLY begins after the engine has warmed up. also, the dash lights are not effected by this at all.
until yesterday, only one of my head lights worked when on low beam. the low beams would NOT blink, but the high beams (both headlights worked) would blink. so i replaced the headlight that was not working. so, now that both work, they both blink.
does anyone have any idea what this could be? are the headlights heating up and causing a short circut of some kind? is it a fuse? a relay?

thanks for your help.

 

[SteveL]

check the switches. The high beam switch on the floor is usually the first to go. Otherwise could be the switch ion the dash. When it acts up reach under dash and wiggle the wires on the back of the switch and see what happens.

 

[broncnaz]

Change out your headlight switch it has circuit breakers in it for the head lights they get old and once warmed up it will blink the headlights on and off. Also make sure all the grounds are good. one way to prevent this problem is to install relays for the headlights you will get brighter lights and should never have a switch problem again.

 

[natec73]

thanks

thanks guys. i just checked some old posts and it seems like this is a common problem. i'll go replace the headlight switch today.

 

[Tiggitytam]

Headlight harness

I had the same problem in my '76. Went with the Extreme Harness from Broncograveyard and all better.

http://broncograveyard.com/bronco/i-18095_extreme_headlight_harness.htm