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My 65 has a shocking habbit of the lights going out while driving down my deer infested Virginia rural route. Not fun. It seems like it happens when I am running high beams. The dimmer would be the first thing one would think of causing that problem so I replaced it. The old one had a sloppy click. Just didnt feel right. I was proud of the new install with perfect action till tonight. Lights out again! I guess I need to think about the headlight switch since when this happens my hasty reaction is to franticly push the switch in and out and they pop back on.
Very common problem in these trucks. The Circuit breaker inside is weak and is cutting in and out. Replace it with a new switch. Also make sure your grounds are good as bad grounds for the lights create resistance which equals heat and light switches hate the heat.
also look at the tech articles for the one about headlight relays (brighter whites,,,,). We have done this to 3 of our old trucks and it makes a world of difference. We live in the country and it is nice having bright headlights on these open roads.
He mentioned he replaced the dimmer switch, so I think it's either a bad H/L sw. or bad grounds. The 73-79's are notorious for this. The later 80's trucks will melt the harness under the dash and start a fire if your not careful.
The 73-79's are notorious for this. The later 80's trucks will melt the harness under the dash and start a fire if your not careful.
Barry
Gee Wizz you would think that after all the amazing things that happened in the automotive/electronics world in the 20th century that Ford could have figured out how to design a reliable lighting system. I can understand a 40 year old truck having some issues but MELTING HARNESSES in the LATE 80s. WTF??
Anyhow I took my switch out and sprayed contact cleaner in it and worked it vigorously back and forth. Works for antique radios and old TV tuners. It doesent work on my Ford. Actually they only went out once all night which is better but not good enough.
If, and this is a big if, the new switch doesn't work check your ground. But I'm pretty sure it's the switch. My headlights would go out if I hit the brakes hard enough, or punched the gas. Took me a week to figure it out...after replacing everything from the cab to the headlights.
Here's a suggestion to test the headlight switch. Wait at idle for a few minutes till the normal time elapses and the lights start blinking. Disconnect one of your headlights and see if the blinking stops then you'll know the current was reduced and the bimetallic switch stays closed. My truck does the same thing and I just haven't made it down to the Au+ozone for the $11 switch. After all, how long before a new switch will be needed? I completely agree with the relay upgrade if you want to go with the brighter whites and it wouldn't hurt to have a fuse as a backup on this circuit. My wiper's bimetallic switch fused together and lukily only took out the switch.
Steve
Quite possible is headlight switch, but sometimes high resistance in wiring or connectors causing switch to fail. If new switch fixes it I would still I check all connectors and grounds.
BB1