Head light problem

[Dagboy1]

I acquired a gama goat a few months ago and have been slowly bringing it back to life. The problem at hand deals with the right head light. It worked initially with the original head light bulb, but it soon smoked out. I bought a new one and it smoked out in seconds. I then did some research on this site, reading many forums, as well as talking to people who seem to know a thing or two about military trucks and 24v systems. Everyone points to a bad ground. So, i just bought a third bulb, but before plunging it in, I put a volt meter on the high beam and low beam power leads. I got 24v. I plugged in the new bulb into the high/low, but left the ground unplugged. I then ran alligator clamps straight from the ground at the battery to the ground wire of the bulb to ensure a perfect ground. I flipped on the lights and the bulb began to smoke inside. I shut it off immediately. I tried the high beam, same thing. This is where it gets really weird... I then unplugged the ground all together. tried the lights. They came on, but started to smoke. I quickly turned them off. Wiggled some wires, tightened a ground wire for the left head light (grasping at straws) and tried again with the ground unplugged. No light. Hooked up the ground to the battery again. Turn lights on. More smoke. Sorry if this is hard to follow, having trouble following it myself. If anyone could shed some light on this it would be greatly appreciated.

 

[m38inmaine]

Sounds like a hot wire is shorted to ground. Take your meter set to continuity, disconnect the battery and with the headlight switch in the service drive position check from each light hot wire to a good ground, if you have continuity that's where your problem is. A bad ground would show up as a dim headlight, flickering or just not working at all. It being 24v is no more difficult or different than any other automotive wiring system, it's just 24v not 12v. I had to rebuild my entire Gama Goat wiring harness and the multi meter is your friend, learn how to use it and you can fix any problem on your machine. It would also be a good idea to print off a copy of the wiring schematic and study it, I enlarged mine to make it easier. Would like to see some pictures of your machine too.

 

[Dagboy1]

Ok, I did that, and I have continuity from both hot wires grounding to the bumper. Just to be thorough, I also did it with the light switch in the off position, same thing. Does that mean the problem is somewhere between the switch and the light? Also, I dowloaded the TM from this site and found the wiring diagram but the page I needed doesn't fully show up. Its funny, theres numbers that show up, but no lines indicating the wires.. Figures, the one page I need haha! I will try to post some picks of the goat soon. its in relatively good shape except for the floor of the carrier, which was used as a dump truck for a local cemetery years ago.

 

[Jericho]

There are no secret relays or switches in the system. To smoke the light if the ground is good you would have to have a interimtent short or an over volt condition As mark said grounds biggest problem. Imagine a good power supply, 24 volts pushing down line to a floating partial ground. Amperage just keeps coming. May as well be a welding rod . check your battery wiring sequence ,confirm your main frame body grounds. Check the power distribution buss bar for condition at the rad end of the cab . Run a multi meter in paralell with the power in lead at head light. And ground side set for continuity. Turn on light. Watch volts with meter and Amps with amp collar input to light. And watch ground continuity. You will find your problem . Biggest problem with aluminum body is grounds. Three way switchs are number two. Had better luck with the three lever styler no luck with the button selector ones

 

[Dagboy1]

 

[Dagboy1]

Those are some pics of the goat before I brought it home

 

[combat32]

Nice looking truck, if you have a spare 3 lever light switch try swapping it out, they do fail sometimes, mine was bad.

 

[Dagboy1]

Thanks combat32, it needs a little love, but it runs and drives great! Not too bad for something that hadn't run in 15 year and sat outside all its life. I don't have another switch, but I may try to pick one up just to rule it out.

 

[Dagboy1]

Thanks for the suggestions Jericho, I will dig into it again this weekend and let you guys know what happens..

 

[m38inmaine]

Nice looking machine, I hope you leave the paint the way it is I love that original look.

 

[quarkz]

Nice looking goat. Congrats!

Gotta go back to basics.
Are you using 24v head lamps?

To make the filaments smoke you would have to put more than 24vdc into the bulb.

With jumper wires (hi, low, ground) directly off of the batteries, can you light the lamp without smoke?

Sent from my MotoE2(4G-LTE) using Tapatalk

 

[Dagboy1]

Thanks! Good question. I bought the head lamps from a military supply place in MN, and it's hard to read the back of it but I think it says 28V. I will try hooking out straight to the batteries tonight and post the outcome. Thanks for the input.

 

[Bighorn]

Thanks! Good question. I bought the head lamps from a military supply place in MN, and it's hard to read the back of it but I think it says 28V. I will try hooking out straight to the batteries tonight and post the outcome. Thanks for the input.

Why not see if they work normally on 12 volts first?
That way you aren't destroying perfectly good 12 volt bulbs if they are in fact, 12 and not 24 volts.
If they light up dimly on 12, then you try them on 24volts.

 

[Dagboy1]

Ok, so I just hooked up the bulb to a 12V battery and the bulb smoked out. What is going on? Cheap bulb? This is the second one I've gotten from the same place that smoked out.

 

[Dagboy1]

Is there something wrong with the battery I'm using?

 

[Bighorn]

Ok, so I just hooked up the bulb to a 12V battery and the bulb smoked out. What is going on? Cheap bulb? This is the second one I've gotten from the same place that smoked out.View attachment 701578

Well, the writing on the bulb does say "Made in China".
Maybe they were dropped.

 

[quarkz]

Well that sux,
this shouldn't be that hard to make work.
It should work on 12v, but just glow orange, not smoke.

On the back of the sealed lamp.
The 3 wires make a u shape.
Bottom side is ground.(91).
Right side is high beam (17).
Left is low beam (18 ) .

you could put a 20A fuse inline with one of your leads for your next testing, on a 12v headlamp they use a 10A fuse in the circuit.

TM 9 -2320-242-20, page 2-53 (or 72 in the pdf) has the headlamp trouble shooting guide.


The military does most everything for trouble shooting as plug and play.
One thing they say to do, is after a bad part is removed, plug it into another known working vehicle to see if it is the lamp or the circuit it plugs into.
Do you have another MV to plug the sealed head lamp into?
Do not plug it into anything with an H4 halogen bulb.
An H4 bulbs has the ground and low beam swapped.

I went out an measured from low to gnd is 1.1ohm
and high to gnd is 2 ohms.
I got a dim and dimmer using just 1 12v battery and then it worked fine with the two 12v batteries in series.

So if you put a ohm meter from ground on the lamp to high bean or low beam it should 1 to 2 ohms.

My lamps were wagner, no part# other than 2D on the glass.
the spec for the 4863-1 look correct.
https://www.interlight.biz/light-bu...DhE_lmejt0gAJvjAKF4kmjusVRoCEUYQAvD_BwE#Specs

 

[Dagboy1]

When I get home tonight, I will remove the working left side headlight, hook it to the 12v battery. If that goes well, I will hook it to the right side outlet and see if I get smoke. If no smoke, bad bulbs right? Where should I go to buy bulbs made in the USA?

 

[quarkz]

Measure the resistance of the filaments before you burn out bulbs.

You have the left side working correct?
If so, put the new bulb on the working side and see if it still works.

Napa, batteries & bulbs, online MV parts dealers,semi truck parts store are all good headlight sources.
Use the part number off of the left side working bulb.
Just make sure they know its 28V sealed beam, not H4 halogen

 

[Dagboy1]

Update: Bought USA made bulb. Problem solved. Thank you everyone for the help!