M35a3 lights flicker

[Msf North Carolina]

I have led lights in my M35A3 1992 like this when I bought it. The headlight cut off when truck ideals down and come back on when it ideals back up also when driving ... any help would be appreciated thanks

 

[ncfirefighter140]

Is there a resistor wired in line to each headlight. If not you will need them in order to get and keep the proper voltage to the headlights. Also if there is one in line it could be going bad and also make sure they are secured in place and not just flopping around.

ncfirefighter Southeastern North Carolina

M35A2
5ton soon

 

[sue]

I have led lights in my M35A3 1992 like this when I bought it. The headlight cut off when truck ideals down and come back on when it ideals back up also when driving ... any help would be appreciated thanks

LED lights are not the best for dimming,
What that means is that you need a
Minimum voltage to keep them “on”
I’m guessing that at low RPMs your
Alternator is allowing the voltage to
Drop down a little?

 

[Ajax MD]

What @sue said. LED's operate within a "range." At idle, you're dropping out of that range, below the minimum.
Your generator may be able to be adjusted to keep the minimum within the range.

I'm pretty sure the generator(?) voltage regulator is adjustable but I haven't done detailed research into this because I haven't had any problems yet.

 

[davidb56]

If your alternator /regulator is working correctly, you should have close to 28vdc at idle. Check that and eliminate a low voltage source problem. Then work your way up to the lights checking the voltage at idle. Ive seen faulty regulators cause idle voltage problems, low idle rpms, and even a undersized alternator pulley cause low voltage at idle.

 

[Msf North Carolina]

Is there a resistor wired in line to each headlight. If not you will need them in order to get and keep the proper voltage to the headlights. Also if there is one in line it could be going bad and also make sure they are secured in place and not just flopping around.

ncfirefighter Southeastern North Carolina

M35A2
5ton soon

No resister, I'll go get one and try that ... thanks

 

[Msf North Carolina]

No resister, I'll go get one and try that ... thanks

OK I checked everything in my regulator O my alternator is overcharging and when it does it shuts the lights off on my headlights and tail lights but when it goes back to green everything runs as normal

 

[Msf North Carolina]

OK I checked everything in my regulator O my alternator is overcharging and when it does it shuts the lights off on my headlights and tail lights but when it goes back to green everything runs as normal

Is it best just to replace the regulator or get a whole new alternator set up

 

[ncfirefighter140]

No resister, I'll go get one and try that ... thanks

You will need one for each light.

ncfirefighter Southeastern North Carolina

M35A2
5ton soon

 

[Msf North Carolina]

I tried putting from own but then I noticed my battery over charge any my alternator may be my regulator is bed

 

[davidb56]

Is it best just to replace the regulator or get a whole new alternator set up

If the alternator is overcharging, its because the regulator isn't working. I'd replace the regulator, unless you have deep pockets and just want to do them both together....some people do.

 

[Msf North Carolina]

If the alternator is overcharging, its because the regulator isn't working. I'd replace the regulator, unless you have deep pockets and just want to do them both together....some people do.

I'll stick with just the regulater..

 

[Msf North Carolina]

I'll stick with just the regulater..

If I can find the right regulater

 

[davidb56]

when mine takes a dump. I'll find a late model aftermarket alternator/regulator, even though it may not be "submerge proof", it will be cost effective to replace when it goes out.

 

[Msf North Carolina]

when mine takes a dump. I'll find a late model aftermarket alternator/regulator, even though it may not be "submerge proof", it will be cost effective to replace when it goes out.

Where did u find urs

 

[davidb56]

I have a A2. I just noticed you have a A3. I haven't had to change mine, so I haven't researched it too much, but I figure I can modify something to fit, not OEM for around 250$. yours is about 5-600$ for OEM type, so I would personally go the regulator route first. I read somewhere that when the alternator itself starts to go, often you will get high voltage ( 30+). If thats the case, then you'll end up replacing the whole unit. research replacing it with a aftermarket (not chinese) prestolite or delco unit before you buy anything.

 

[HDN]

I'm not too familiar with M-series LED replacement lamps. Would they really need a resistor? I'd think that a resistor would be built-in to the lamp as being one less part to screw around with.

It's one thing when working on a vehicle with CANBus, but for something as simple as an A3? I'm surprised a resistor is even needed. Unless I'm missing a detail about the OP's LED lamps...

 

[ncfirefighter140]

Some come with them built in some don't. Mine in my F250 did but I have seen some that didn't for military truck use. You can tell if there is one because there will be a in line box or one wired in line. Either way you would know and see it if it was there.

ncfirefighter Southeastern North Carolina

M35A2
5ton soon