Oh no! Intermittent headlights...

[Bamtech1]

Twice now the headlights have just gone off briefly and back on. That’s just the twice I noticed.
Is this a common failure, is there a known likely fix? It’s hard to diagnose a ghost like this, and I’m about to embark on a lot of night driving vacation.
Should I throw a headlight switch at it?

 

[GrantP]

Headlight switch is a safe bet. I had to replace it on my 97, same problem.

 

[DavidC]

Could also be the multifunction switch. Seems I had to flip mine a few times when going high to low beam

 

[petersonj]

I am for the headlight switch, if it has never been relayed. You are witnessing the action of a cyclic circuit breaker in that circuit for safety reasons.

- John

 

[BarryG]

Mine was wigging out over a few week period of time no high beams, then no low beams but the high beams came back then in the end the dang things wouldn't shut off. Had a multi function switch laying around for some reason and figured since it was the high beams giving me trouble at the moment that would be a safe bet threw that in no change. So got a new headlight switch still no change. Just as I was about to get really irritated with it since they wouldn't shut off I finally remembered that many years previous I had put a Bright Box on it (allowed high and lows to be on at the same time or highs and fogs whatever it was don't remember now) unhooked that and all was well. So I took it out opened it up and it was all corroded on the inside of the little box. Don't forget that most of the 2nd gen headlights were negative switched but that may have just been the later ones. If just the high beams acting up I would think multi function switch, could also be a bad wire in the steering column harness if you have a tilt wheel. I had a couple break on mine as it aged but was able to repair them but don't remember if the multi function switch wires are part of the tilt portion of the column or not. However if low beams are shutting off I would suspect the headlight switch or a bad ground somewhere else in the circuit.

 

[BigPapa]

I’ve had to replace my headlight switch AND the CONNECTOR on both the 2nd Gens I’ve owned. And, come to think of it, I also had to replace the headlight switch on the 1st Gen I picked up a couple of years ago. All exhibited terminals that had been extremely hot. I’ve put relays on my ‘98.

-Scott

 

[Bamtech1]

Thanks for the insight. I may just buy both switches. Relays are mentioned, is there a kit or a how-to writeup?

 

[Joe Mc]

After many years (owned since 05/01) I replaced the headlight switch (about 8 years ago) and most recently added the bright box (highly recommended for ease of installation, improved visibility and a proven accessory = if Geno's sells them...). About 3 years back I had the rust remediated (new fenders, driver door, bed wheel arches and a few spots on the passenger rear door) and painted my truck. I also installed some aftermarket headlight assemblies (forget manu?) which are of the 2 lamp/assy type. Having the hi/low and fogs on at the same type really helps on those desolate dark highways and byways. Don't get me wrong, the lighting isn't like the new trucks with their HID/LED but you sure do see better and even with all on you ain't blinding other drivers...

 

[BarryG]

As far as the headlight relays you can pick up your own or go with a kit. As Joe mentioned if you don't have the sport headlights it is a worthwhile upgrade. If so obviously the oem sport headlights are the way to go if they are even still available but they are pricey iirc when I upgraded mine they were stupid priced like $250-300 each and the Light Depo ones I got were around 150 for the pair but it has been quite a while so that may be different. I had no issues with my assume Chinese TYCO knockoffs and they are still working today at least 10 years later.
I used Daniel Stern for the relay harness had him build it. It was very high quality though he does sell just the parts and you put it together his website has a lot of great info on auto lighting. Below is a link to the use of relays but check out his whole site it is informative
https://www.danielsternlighting.com/tech/relays/relays.html

There are or at least were others that offered a similar relayed harness but from what I remember they were not as high quality summitt, LMC to name a couple. A search on here about sport headlight upgrade would probably yield a bunch of threads. The upgrade is a pretty straightforward swap, plug and play even the 2nd gen models prior to the sport lights option can use them just have to do a bit of sheet metal cutting in the headlight bucket so they can fit the additional size but once it was an option (thinking 98 and later) no cutting required.

Here is one of them from headlight depot at less than $60
https://www.headlightsdepot.com/199...500-passenger-side-sport-combo-headlight.html
note that it says a conversion harness is required their conversion harness does not add relays it just adds a plug to allow power/ground to get to the other bulb sterns harness has it all together including relays

 

[BigPapa]

Thanks for the insight. I may just buy both switches. Relays are mentioned, is there a kit or a how-to writeup?

Not saying it can't happen, but I don't know of anyone besides DavidC that's had to replace the Multifunction Switch for failing headlights.

As to the relay harness, I made my own but LMC Truck also offers one for $30.00.

http://www.lmctruck.com/icatalog/de/full.aspx?Page=53

 

[Rich Poirier]

look for the purple wire barely hanging in the switch harness. If you use your tilt alot like I do, it works the purple headlight wire from its plug. Throw her back in there good, and make sure its in there good for the future. good luck

 

[PBJ2500CTD]

Not saying it can't happen, but I don't know of anyone besides DavidC that's had to replace the Multifunction Switch for failing headlights.

As to the relay harness, I made my own but LMC Truck also offers one for $30.00.

http://www.lmctruck.com/icatalog/de/full.aspx?Page=53

I changed both my headlight switch and multi-function switch at the same time back in 2015 on my 2002.. Multi-function due to low-beams going out while driving down the road on a moonless night with oncoming traffic (thank goodness for fog lights), and the headlight switch for no dash switch illumination. A couple months prior I helped my oldest son change the multi-function on his 2006 3500 Mega Cab for the same issue.