HMMWV Battery Drain Overnight

[ltrpd]

My 1987 HMMWV is draining both batteries overnight. I have read other posts here and have taken the following action. I have checked the draw from the vehicle when off by
using a meter between the negative battery and shunt. It is drawing 2.06 when off. I disconnected the light switch and the Nartron box and still the same draw. Please help, Ralph

 

[Retiredwarhorses]

That really only leaves your starter and Generator....

 

[TedG]

Once you isolate the gen and starter (one at a time) and you still have the draw, then check wires and bulk head fitting for 24vdc positive stud. An assumption is being made that you do not have a 4L80e and TCM.

 

[ltrpd]

Thanks everyone, I disconnected the starter and it was still drawing power. So does this determine my starter is defective? Why is it drawing power. I also broke the small wire on the alternator by over tightening it can the top be replaced or is it time for a new generator. Thanks for all the help, Ralph

 

[papakb]

Ralph, your post says you disconnected the starter and it's still drawing power. This test eliminates the starter as the source of the power load. Now disconnect the large 8 gauge wire to the alternator stud (under the cover). This applies to the 60 amp alternator. This test will determine if your alternator is OK or not.

You can also read the shunt current on the STE/ICE plug between pins X (+) and W (-).

For safety, always disconnect the batteries when installing or removing the Control Box or EESS boxes and the alternator cables.

 

[ltrpd]

Papakb, I mistyped, I disconnected the starter and it was the cause of the drain. Is the whole starter bad or other components in it, Thanks,Ralph

 

[kfrosty]

ltrpd, your alternator charging wire connects to the starter so no it doesn't mean it's your starter just yet. I would connect everything back up and then disconnect the wire from the alt to the starter and test first. If you have a 200 amp alt, then just disconnect from the terminal. If you have the older style, then I would just disconnect the wire at the starter positive terminal instead of taking the cover off the alt.

In my case, I learned that most likely the diodes in my alt are probably bad.

 

[papakb]

The battery leads connect to a couple of large copper buttons inside the starter and as the starter actuates they tend to sputter copper inside the solenoid housing. If bit of that got into the wrong place they'll cause the starter to draw current. You can also get carbon from the arcing that is also resistive. Unfortunately this means dropping the starter but rebuilding or replacing the solenoid isn't all that difficult. Dave Walker at Walker truck Parts has rebuild kits and the solenoids themselves are available online.

Kurt