what would make the high beams flicker off/on?

I put the low beams on, and then cut my bright lights back on,

its a 5 speed so it has the high beam switch in the floor.

would it be the high beam/low beam switch causing the problem?

or the switch on the dash to cut the lights on?

hope its not a shorted wire or something...

what do you think?

anyone else had this problem?

 

manufacturers moved those switches up from the floor because they tended to get badly corroded after a while . it would be the first place i would look.

 

+1 floor switch

 

it could be the dimmer switch, or it could be the connections at the switch.

 

Headlights don't use a fuse, rather use a circuit breaker so it'll automatically reset if there's a short OR too much load at the headlights. That way you're not left in the dark if there's a problem.
SO, if the low beams work OK I'd suspect either a foot pedal high beam switch issue, a wiring issue, or some mods to the high beams on the truck drawing too much current.
If there are low beam issues also then look somewhere upstream, like the headlight switch itself - they do tend to "burn up" but they're relatively cheap, easy replacements.

 

I have had the main head light switch go bad or "burn up" as posted.
Also as said it has a breaker that resets so how do you know it did not reset when you switched from HI to LOW beams?


Hi beams pull a lot of power and can make the breaker tip sooner then on low beams.
Try putting more load on the system like trailer lights and I bet the breaker will trip on low beams, the breaker is just not weak enough yet to trip on low.


The floor hi/low switch is just that a switch between the 2.
Power from the main switch goes in and when it comes out it is either hi or low beam. I have never seen one stop working in the middle of being used, unlike the main switch, but have seen them only work on 1 side or the other or both not work.


Because both are cheap I would replace both but money in on main switch.
Dave ----

 

well , when I went to replace my switch in the floor board, I found a hole in the floor board in front of the switch!

so I bought 2 , 18 gauge steel square panels, and booger welded a patch panel in with the mig welder, and then used some metal seam sealer around the panel I made, and I did a small patch on the passenger side floor board too.

I might buy a roll of cargo mat carpet for like $10, and re-do the carpet in my truck while I'm at it.

haha.

I'm thinking some water might have got in the switch. it was corroded on the bottom.

 

I use to drive the E-150 for a courier company at night back when those were new, and that happened a lot. Mechanics replaced the floor switch, and all would be good. Those Vans ran 24/7 and the flaws showed up pretty early.