m998 3 amp battery drain question/help

I have a 90 m998 that was running and starting great with no issues, I replaced the rear,front and side marker lights with LEDs and all of a sudden i have a 3 amp parasitic draw, I unplugged the alt. (60 amp) from system and draw goes away and the protective control box the draw goes away.
I don't want to through parts at it, my question is could the box be my problem or the alt. and how do you isolate them. my alt. was charging 27.5 volts and amperage verified full load 35-40 amps (seems low to me ) no glow plug issues.
where does the charge wire from alt. go? anyone have any ideas for me? thanks for your time.
Robert
St. Pete, Florida

Did you put the standard lights back in and see what happens? I would first eliminate the thing you changed that caused the problem. You may need a resistor for the LEDs.

The old light were in pretty bad shape I can't reinstall them

See if voltage is present at the alternator excite wire with ignition off. If so, the draw is from the alternator, but is the normal draw. The protective control box may be sending the power when it is not supposed to. I really don't think installing the LEDs is related. With the master light switch off, the vehicle has no idea if there are LEDs or not.

When I unplug the excite wire the small one with the boot the draw goes away there is battery voltage at both excite wires and the starter wire

Others here need to chime in before you replace anything, but I believe the protective control box is to blame. The alt is ok.

I am also leaning that way. Just was hoping it was something simple and cheap. Thanks for your help

Look at your dash at night. Are the dash lights on?

No lights on and switch unplugged does not drop the draw.

Are you unplugging the switch, PCB, alternator, etc with the batteries still hooked up?

Never.

I am a diesel technician I have a high and low amp probe I did as you stated and when you unplug the box the amp draw goes away also when you unplug the alternator the amp draw goes away I don't have schematics to see how those two work together to isolate which one it is and I don't want to throw Parts on it that it does not need the alternator Exciter wire has constant voltage which leads me to believe it is the Box stuck on causing the drain

If unplugging the control box makes the draw go away then it is the prime suspect. The alternator is the "dumb" load in the circuit (which I believe you already know) like the light bulb that stays on when the switch is definitely ​off (because the switch is bad inside). It's where the draw is occurring but not why.

Sometimes a little affirmation is good thanks for the help I got to control box, I'll be curious to take that one apart and see what's inside

Great info thank you. Thinking about it when I strip the truck down for paint I didn't disconnect the batteries and I pulled all the lights should have did my research first thanks everyone for the help

Lots of electrical stuff in the HMMWV runs through the PCB. Thus unhooking that, could disconnect anything that is really the problem.

What alternator do you have? Does it have a dual voltage regulator? Are there any wires connected to the regulator 14 volt stud? There is a reason I am asking and I will explain if you do