Tail light issues on newly acquired m998

[comanderfritz]

So I took the dive and bought a HMMWV to mess around with for awhile. So far I'm loving it and figure it was a good decision. I guess we shall see. Anyhow, first issue with it i need to address among many is I'm having rear light issues. My manuals haven't arrived yet and I'm not sure if they would help or not anyways. So when I first got it earlier the rear lights would not light up in any mode. So I messed with it a bit. Turns out they are the new style lights and have a ground cable that doesn't correspond to any ground cable off the vehicle. So a dangling line. So first thing I did was test this and it read 24 volts coming off of the light. I figured I'd ground it and see what happened. When I did the light lit up like the breaks where on permanently in both road modes. However it shuts off in blackout modes and the blackouts worked. When I applied breaks, turn signals, and day-night... those made no difference, it stayed on bright. Same story with the other side except it doesn't come on when grounded except an occasional light flicker. But blackouts work. So I'm figureing this is an easy fix of some sort I'm just too much of an electrical noob. Any ideas?

 

[NDT]

Stop light switch under dash may be misadjusted.

 

[Bravojmc]

Stop light switch under dash may be misadjusted.

Good call

 

[comanderfritz]

I'll check that out in the morning.

 

[papakb]

The brake light switch on the HMMWV is a pretty bad design. There's no free throw adjustment on the linkage to compensate it's travel so if the brakes are correctly adjusted you can have them stopping you before the lights come on and if you adjust them to come on it'll stand you on your nose. All of the lamp current goes through the switch and they wear quickly making even properly adjusted switches require occasional readjustment. One of the simplest things to do to eliminate contact wear is to install LEDs in place of the standard lamps or replace them with the newer LED models the government uses.

 

[comanderfritz]

I found it. thing wasn't hooked up. Still doesn't work. Seems it either has two adjustments. Hooked up or not hooked up. I suppose I could make an adjustment. Alright seems I've got a place to start from. Thanks.

 

[comanderfritz]

Still cant get the left light to work. I don't know how I can ground it any better. Found out hazards and turn signals don't work at all anywhere. Right rear light will light up when break applied. Then go off. But then won't light up again when break is applied after that. These are the new gov LED lights I'm working with. I think I have larger problems.

 

[NDT]

You left out important details: you have LEDs and the turn signals don't work. There are several threads here on getting LEDs to work.

 

[comanderfritz]

You left out important details: you have LEDs and the turn signals don't work. There are several threads here on getting LEDs to work.

that's what came with it so i wasn't aware it was a different ball game. Now I know though and am looking in to it. No bueno as of right now. Thanks again.

 

[daniel.7575]

Still cant get the left light to work. I don't know how I can ground it any better. Found out hazards and turn signals don't work at all anywhere. Right rear light will light up when break applied. Then go off. But then won't light up again when break is applied after that. These are the new gov LED lights I'm working with. I think I have larger problems.

You could try swapping out your light switch unit, these can be faulty and cause all sorts of issues.. Make sure you disconnect the batteries before swapping out electrical components!!
Also as mentioned search for previous threads on LED light issues..

 

[Action]

You left out important details: you have LEDs and the turn signals don't work. There are several threads here on getting LEDs to work.

He told us in post 1 that the ground wire from the lights wasnt connected. The regular lamps dont have a ground wire, do they?

 

[comanderfritz]

It is acting like there are shorts. But what puzzels me is the turn signals not flashing in the front but lighting up solid, the blackout lights working but not the main tail lights, one rear light working sometimes when it feels like it, but not the other and my wipers work sometimes but not others. I think I am looking at multiple problems. Maybe with the flasher switch and light switch. Or could I not be getting a good ground on everything? Or the whole thing Is covered in shorts. I looked over the LED light threads, I tried some of those things. But I really couldn't find a similar one to what's going on with this truck. If you all know of one please send link. As of right now I guess I'll start with the switch box. Would It be a good idea to try using regular lights instead of the LEDs? Do they draw more power or something that may be messing with the whole system? I could care less about them I just want to be road legal at this point.

 

[NDT]

"Shorts" is +24 volts going straight to ground. Lots of fireworks with this. You have intermittent connections. Wiper, replace or eliminate the contacts where the windshield folds. Your lighting issue now sounds like a bad turn signal control handle.

 

[dilvoy]

Led Tail Lights and Front Led Turn Signal Lights need the electronic flasher unit. It has smaller cooling fins on it than the old style flasher Units. Even with that, I found that I had to remove the little light bulb from the Turn Signal Unit to make everything on the exterior lights work. Putting a little Led bulb into the Turn Signal Unit made things not work properly again so I just left the bulb out and all is good. It's easy to do if you can get your fingers around that little bulb to get it out. If you are worried about forgetting to turn off your turn signals, you can get a Turn Signal Upgrade Kit that makes the signals cancel after a turn like a normal car would have.

 

[comanderfritz]

I tried taking out the light bulb and it didn't make a difference. However I am sure I don't have an electronic flasher unit. Everything is unupgraded on this except the new led tail lights. Looks like my best bet is to replace the flasher unit and check the turn signal control.

 

[jeffy777]

I tried taking out the light bulb and it didn't make a difference. However I am sure I don't have an electronic flasher unit. Everything is unupgraded on this except the new led tail lights. Looks like my best bet is to replace the flasher unit and check the turn signal control.

I am working on an almost identical problem. I am very interested in what you find. I have the electronic flasher although I did not take out the bulb. I was planning on working on it last week when I had problems with my front drivers-side geared hub. If I get mine fixed I will try to update you, I plan on working on it this next weekend.

Thanks,

 

[86humv]

LED light test :
Tested the directional lights and found :
With all four Grote led's , and a incandescent light bulb in blinker switch : thermal switch made by Swiss controls [ 12418344 ],
Aurora Cord [ 11613631 ], and Riverside Mfg. [ 11613631 ] lights work as they should.
The Nartron 11613631 won't work, unless you change the 1819 incandescent bulb in the blinker switch with a 28 vdc LED bulb.
First pic is a Nartron
Second pic is others listed above.

 

[jeffy777]

LED light test :
Tested the directional lights and found :
With all four Grote led's , and a incandescent light bulb in blinker switch : thermal switch made by Swiss controls [ 12418344 ],
Aurora Cord [ 11613631 ], and Riverside Mfg. [ 11613631 ] lights work as they should.
The Nartron 11613631 won't work, unless you change the 1819 incandescent bulb in the blinker switch with a 28 vdc LED bulb.
First pic is a Nartron
Second pic is others listed above.
View attachment 675999
View attachment 676000

Now you are saying the blinkers will not work. I am not getting the break or running lights to work. How would the blinker switch bulb effect the break lights or running light? I will try that but I am getting nothing out of my left rear drivers side light. (Just asking because I am not HMMWV smart yet )

 

[daniel.7575]

When I got my truck all the lighting system was a real mess, looked like front end had been submerged.. I fitted new hood wiring loom, LED headlamps, Riverside LED front and rear lights, LED yellow side markers on hood and standard non LED red rear markers, standard flasher unit, standard indicator control. All works as it should.

 

[comanderfritz]

Had to work on my power steering first. This I'll work on in the next week or two and will report results. I ordered a new turn signal unit and a new blinker switch.