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headlights turn off while driving

reamesc

New Member
Joined
Jan 30, 2014
Messages
35
Loc.
Columbus, GA
i have noticed alot lately that ill be driving to a friends house at night, and not only do all of my lights flicker from dim to bright, but my headlights turn off for a few seconds and then turn back on later on. what could be wrong with the wiring of the circuits? i would prefer to also solve the flashing of all sidemarkers and turn signals as well. my best bet is that the relay is bad but it could also be the switch
 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
51,619
About 90% of the time, this is due to the old headlight switch with it's internal circuit-breaker either not being strong enough for some higher load lights, or just plain wearing out.

Three things to do then.
1. Install a relay system like we and the other vendors sell. (Takes the load off of the old switch, and brightens the lights, so do it no matter what you do with 2 and 3)
2. Replace the switch. (helps for awhile, but do the relays from #1 anyway)
3. In the meantime, when it happens on the road before you fix it, unplug one of the headlights and that should temporarily get you home without the on/off/on routine. (but do the relays anyway - sensing a theme here by any chance? ;D)

Good luck.

Paul
 
OP
OP
R

reamesc

New Member
Joined
Jan 30, 2014
Messages
35
Loc.
Columbus, GA
ok, i will start out by replacing the relays and maybe get a new switch later but how do i install the relays and which set is best? also will the relays be behind my dash or in the engine compartment
 

Quick & Dirty

Sr. Member
Joined
Feb 15, 2004
Messages
857
Stock wiring has no headlight relays. That's the problem. Upgraded modern headlights draw more current than the originals, overloading the headlight circuit breaker. You need to add relays to the system so the current doesn't go through the switch.
 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
51,619
Here's one of our versions. Should be pretty easy to install in general. Just have to run the wires clean and out of the way entirely under the hood. Kind of plug-n-play though, other than that. Simply use your existing headlight wiring to trigger the new relays.

http://www.wildhorses4x4.com/product/NightLighterHeadlightHarness

When I had the same problem as you, I did the relays even before changing out my switch. Funny thing about that, but I'm still using that same switch! Even at it's advanced age, taking 95% of the electrical load off of the headlight switch and dimmer switch really increased their lifespan.

Paul
 
Last edited:

gray gables

Sr. Member
Joined
Aug 7, 2013
Messages
742
mine did that one night at about 2 in the morning in the back roads, stayed that way for about 15 minutes, wasn't fun. The next week I put in a brand new harness, a painless, which I now call PIA
 

Rustytruck

Bronco Guru
Joined
Feb 24, 2002
Messages
10,872
Sometimes these issues crop up with the dimmer switch on the floor. All the light wiring goes through that switch. Being on the floor the connections get crappy. Lift the switch and clean up the connections and see if that helps before buying anything.
 

mcknight77

Full Member
Joined
Feb 19, 2012
Messages
219
Loc.
Caldwell, ID
Sometimes these issues crop up with the dimmer switch on the floor. All the light wiring goes through that switch. Being on the floor the connections get crappy. Lift the switch and clean up the connections and see if that helps before buying anything.

X2 on the dimmer switch. It gets wet from feet and corrodes easily.
 
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