Headlight Issue

[cclary25]

I finally thought I had everything solved on this HMMWV I just recently purchased to then notice the front passenger headlight was not on. I pulled the headlight out and check the connections and appeared to be good and put the bulb back in. After moving it around it finally came on and it seemed to work. It appeared to finally be staying on so went to get an inspection sticker and they came and got me and showed me that the driver side headlight was now not coming on. So i got home and checked it again and now for me, the driver side is back to working and the passenger side is not on. So before I spend a few hundred on changing them out for some new LED headlights I wanted to make sure everything else was alright before spending money to replace the lights and then have those still do same thing. Where do I start? Is this some sort of electrical issue since they come on and off at random.

Thank You

 

[LouWon]

Try moving around the arms on the light switch, I was having all kinds of problems, from dim lights to no lights at all, if the lights fluctuates when you play with the switch, replace it.

 

[papakb]

The wiring to the headlights are wires 16, 17, and 91. Wire 91 is the ground lead and needs a good connection to work properly. 16 and 17 are fed from the master light switch through the floor dimmer switch. There's a spray called DeOxit that you can find at Home Defect or Lowes and most electrical supply places that cleans and insures good connections that I highly recommend for all your electrical connections. Make sure to spray both parts of the hood harness connector too. Grounding it a major PITA in the HMMWV and if you haven't already done so read the section in this forum about the supplemental ground harness and then either make one or buy one and install it. It's a pretty simple piece.

 

[cclary25]

Well I just went out and started up to take a look at some other things and noticed the headlights are both coming on just fine however, it now seems that when switch it to high that the driver side comes on really bright however the passager side is really pathetic with barely any light coming out. I actually did install the kascar ground kit this past weekend and went to lowes and purchased CRC Contact Cleaner for using on this grounding kit. Is this crc contact cleaner similiar to DeOxit or should I go back and get that instead. Also, now that it seems to be just the brights on one side is it still most likely a wirring problem or could it be the headlight?

This weekend when have time guess ill start with tracing those three lines and using the spray and getting those all good and eliminated from the equation then guess if still having problem will have to narrow it donw between the switch itself as LouWn mentioned or go ahead and do LED headlight switch a little sooner then was planning.

Thank you

On a side note if its the switch itself could finally have a reason to get the push button switch instead.

 

[papakb]

The CRC is just fine. Check your connections and make sure someone hasn't swapped the 16 and 91 leads both on the back of the headlight bucket and the connections to the bulbs themselves. It's an easy mistake to make. The pushbutton light switches have their own special set of gremlins and one of the biggest is the ground lead that connects to the ground stud behind the heater control panel. Make sure any time you connect or disconnect it you have the batteries disconnected. Simple enough to do by lifting the battery interconnect cable. Instead of a bolt I installed a piece of threaded rod with star washers and nuts on both sides of the firewall. This means that I never have to break the area where the stud bonds to the body.

 

[Action]

the grounding harness is helpful, but it wont fix connections that are already bad around the vehicle.

 

[1977and2010]

Switch headlights side to side to see if it's the light or some other electrical issue. That will rule out the light.

 

[donnerwetter58]

Just to clarify the wire numbers, 17 is high beam, 18 is low beam, 91 is ground. There is no 16.
If 91 is switched with 17 or 18, you will have one position where you’re creating a series connection through both filaments to ground. This will create a dimmed light and typically your high beam dash indicator will be constantly lit as well.

 

[DatGuyC]

On a side note if its the switch itself could finally have a reason to get the push button switch instead.

Don't know if you know it or not but those push button switches have a tendency to short out and catch fire, possibly burning down the whole truck.