Headlight issues

[SKI-'84K5]

So I'm driving down the interstate the other night in my 86 burb and my low beams flicker and both go out. I turn on the high beams and they are working just fine, all four lights.

After reading up here it looks like the low beams are dual filament and most likely they both went bad simultaneously. I have gone through and replaced some of the wiring as well as cleaned up the grounds. MM is showing voltage at both bulbs so I guess tomorrow I will replace the bulbs and see how it goes.

Any ideas as to why they would both just go at once?

Thanks in advance

 

[apache]

Pretty odd, A voltage spike would have burned more than the headlights Id think. A bad ground to the headlights causing higher amp draw??, but then the wire insulation might show some burning also from the heat.

 

[SKI-'84K5]

most likely the increased current draw is what it was. didn't get a chance because of work to pick up the other lights but I did have some crappy wiring in there, just not sure if it was the PO or factory but I am leaning towards PO.

I still plan on switching from sealed beams to "euro" style and replaceable bulbs, probably 9007 and 9005 to retain the 2 light low and 4 light high beams, and the relay mod at the same time.

 

[Slapperbar]

I had something similar happen to my 91. It was the switch.

 

[buffblazer]

Pretty odd, A voltage spike would have burned more than the headlights Id think. A bad ground to the headlights causing higher amp draw??, but then the wire insulation might show some burning also from the heat.

had a 91 suburban that lost both low beams at the same time, driving down the road and bam both went out replaced the headlights and another 90k was put on the truck with no headlight problem.

its odd but it does happen

 

[apache]

Been a while and Im not sure if Chevy is the same but a couple older Ford PU`s suffered the same lights out deal. On those years the switch has a built in circut breaker of sorts so after a bit when things cooled they`ed come back on. Pretty damn scary when they went out on mountain road on a moonless night. Replaced the switch and no more problems.

 

[SKI-'84K5]

well first i replaced the switch out of curiousity and since the other one was definitely "loose" feeling. no change, replaced the sealed beams and they worked fine.

bonus it idles much smoother and starts easier with the grounds all cleaned up, still registers high on the voltmeter so i will take the alt and battery up and get them tested.

 

[k20]

nothing to add as to the problems but I have the e-code hella's and they are amazing. Aint cheap but its night and day compared to the stockers...literally

 

[Mike D]

I wired both low and hi headlights to seperate 30A relays. The headlight switch turns on the relay and the relay turns on the lights. If you use 10 - 12 guage wire and 30A circuit breakers you will take a heavy load off the switch and have briter headlights due to heavier guage shorter wiring.

 

[kennyw]

Another possible cause would be the dimmer switch... actually a very common problem in the older trucks with the floor mounted switch that is always getting muddy and wet.