Agreed. I still bank on the headlight switch! That was my first call in my earlier post. I do think the relay kit is a great idea, especially if your model doesn't have a relay. It takes all the load off the headlight switch and also shortens the wire, thus decreasing voltage drop to the lamp, if placed close to the front of the engine compartment, near the battery. A well $30 spent IMO.

 

I had the same exact issue 2 yrs ago. As long as the lights/switch didn't heat up, I was fine...

But then it just got worse and worse until they'd flicker after 30 seconds to a minute of being on.

As said before though, could be a bad connection.
Replacing the Headlight switch (EXTREMELY simple job) cured the issue.

 

I ended up heading over to autozone and picked up a new connector for the headlight switch. It seems to have cured the problem! I'll have to test it out tonight. That's for all the help guys!

 

Unless the lights DO flicker for both high AND low beams - the problem HAS to be AFTER the hi/low switch. (or AT the switch, but you said you've already replaced that).

Assuming the connection is solid onto the new switch...

Next in the circuit after the dimmer switch, there's one huge, million wire connector where the wires from the cabin come through the fire wall. I'd guess for the moment that that connector is ok - again since so much other stuff comes through it that doesn't seem to be giving you trouble - including your lowbeam wire.

That leaves the wire from the firewall to your headlights.

Assuming both lights flicker together (which is something worth checking by having somebody drive in front of you) then you're almost certainly looking at a bad wire between the lights and the firewall.

The light switch itself provides power TO the dimmer switch. So the light switch is either on or off - it doesn't care about hi/lo. So it stands to reason that since your low beams work fine - your light switch is a known good.

I'd also have somebody drive in front of you want watch to CONFIRM you lights don't flicker when in low beam mode. They MAY and you just don't notice it because they're not as bright.

But given what you said that it's only high beam - if that's true - it HAS to be after the dimmer switch - it's a sure thing that will cut out a LOT of detective work for you.

(one caveat - MAYYYBE the high beam is drawing so much more current that it's heating up the entire circuit and melting something in the switch --- MIGHT happen - but if that's the case, a new switch is only going to mask the problem for a while) - if you DO have high current lights, you should go to relays.

in fact - if you have BURNT connectors - your flicker's either caused by a short somewhere - or you're running high wattage bulbs. You never did say what you have for bulbs - but if they ARE "bright" bulbs - and your connector's burning - you really should go to the relays before you do some real damage. Swapping components for unburnt ones could hide a dangerous situation.

 

Well it was happening with the high beams most of the time. It happened with the low beams a couple of times

 

I would almost bet the cost of a new headlight switch, that the headlight or it's connector is the problem, and if you replace the switch and don't change the connector (if it shows ANY sign of being hot) you will just burn up the new switch...

The connectors cause the switch to heat up when there is a bad connection, be it loose or dirty, and the heat is what causes the THERMAL breaker to trip and flash your headlights.

 

I think he has resolved the problem, correct? The resistance definitely will cause the thermal breaker to trip. I would still upgrade to the relay kit for $30 and you don't have to worry about this issue, ever.

 

Yes, the relay kit is one of the best upgrades that a man can do for ANY headlight system, but especially on these trucks.. I once had a 76 F150 that got a headlight switch about once a year, I cured that sucker, I made my own relay kit, never had any more trouble out of it.