What causes Headlights to go out?

[Flatlander]

Had a 24v headlight go out on my M35A2C...replaced it only to have the new one pop as soon as I turned it on...think it's a bad ground or something?

What should I check with the multimeter?

Just thought I'd ask before replacing it again, cause it's expensive experimenting!

Thank y'all for your help!

 

[SasquatchSanta]

If they are going out immediately upon installation it is no doubt something haywire electrically.

having said this, if your motor is idling too low the vibration will drastically reduce the life of your headlights.

 

[Flatlander]

I checked the two leads aside from the ground...they were both 24.5 volts, so I'm thinking just a bad bulb...unless I bought a 12volt military headlight by mistake!

 

[dk8019]

Ernie,

Question about the idling, mine likes to idle right at 700 rpm, one of the documents I read suggested >800<1000 RPM for idle, but a later -10 suggests that >650<1000 RPM is ok.

 

[kendelrio]

Low light fluid in the reservoir....

 

[scooter01922]

Its not so much where you truck likes to idle that is the issue. I know that mine likes to idle at about 700 as well, that is if i let it. If its going to be sitting for more than a few min at idle just pull out the hand throttle and set it at about 1000. Its absolutely amazing how much less vibration there is at 1000. Try doing a walk around on the truck at the 2 engine speeds and i garantee you will hear less stuff vibrating and see less stuff moving at 1000 VS 700.

 

[Engine5]

If your driving too fast, the wind might be blowing out the flame.

 

[TommyG45]

Boy, it really sounds like a bad buld from the gate. Get a cheap 24 volt job from NAPA, not a deuce head light lamp, and experiment with that, even if you have to solder leads to it so you can connect it in to the electircal system. It cheaper to blow a few bucks then it is 25 bucks to test your theory, besides, then you have yourself a 24v test light.

If your still running into issues, PM me, I will walk through a few more trouble shooting processes with you.

Tommy

 

[Stonewall]

where is a good source for a new headlight. My driver's side lamp is out and I need a new one.

 

[Uglyranger]

$26.95 plus shipping on eBay
http://cgi.ebay.com/ebaymotors/Head...024QQitemZ370128180980QQrdZ1QQsspagenameZWDVW

 

[JasonS]

Anyone think abut adding an inrush current limiter. I have used them on vacuum tube filaments with good success. Bulbs almost always blow at startup due to the quick temperature change.

 

[littlebob]

Check to see if the bulb is blown if you haven't already by checking the resistance between the ground terminal on the bulb and the high and low terminals. If the have continuity on
these your bulb is good. If the bulb ids good you have a bad connection on the + or - side of the wiring. Most problems with DC systems I've found it to be ground(-). I have checked voltage with a voltmeter and no load and got a good reading, but the high resistance of a
a poor connection usually ground will prevent a device from working. Along the same line resistance causes more heat and could burn out filaments in the bulb prematurely.

Good Luck!
littlebob

 

[JasonS]

Wire or connection resistance will not have the effect of burning out the filaments; it will at worst cause a dim bulb.

 

[SasquatchSanta]

I set the idle at 900 RPM. That may be considered high by some but I think it's easier on everything to idle them up.

In the winter when I let it idle to warm up I set the throttle at around 1,100.

 

[littlebob]

Wire or connection resistance will not have the effect of burning out the filaments; it will at worst cause a dim bulb.

Have to admit that part of it was a guess. I have had DC problems that
frustrated me for long periods of time, just trying to point out a posibility.
Thanks for eliminating that one.
littlebob

 

[M543A2]

I have had this problem with an M37 and also with farm equipment. I usually found it was the result of a bad ground.
Regards Marti

 

[M543A2]

A few further comments on grounding:
Make sure the wiring for the light is grounded well. Also, the body needs to ground to the motor. There is a ground strap from the firewall to the back of the engine that is to do that. I also have had fenders that did not properly ground to the rest of the body. About all of the really frustrating electrical problems I have had were the result of a bad ground.

 

[poppop]

My NAPA store and my local big truck parts house can order 24 volt Military head lights. Last one I bought was $24.00 and no freight.

 

[JasonS]

This is informative: http://members.misty.com/don/bulb1.html