Parasitic draw on batteries

[majorhavoc67]

I may have a start box going bad. Is that one of I'm sure many things that can cause a draw on the batteries?

 

[Thunderbirds]

I may have a start box going bad. Is that one of I'm sure many things that can cause a draw on the batteries?

Not likely if you have the original start switch installed. Power should be completely cut off to the ignition system in the ENG STOP position, IMHO. Have you added any accessories?

 

[majorhavoc67]

No accessories added. I do have a bad light switch that I unplugged. There is still some draw on the batteries though.

 

[Mogman]

No accessories added. I do have a bad light switch that I unplugged. There is still some draw on the batteries though.

Simple enough to tell, unplug the engine side then re-connect the batteries and check again, if the parasitic draw is gone then plug that connector back in and then remove the inside connector, if it has parasitic draw then it is likely the box, if it goes away then it is something connected to the inside connector.

 

[86humv]

If the truck has the 4 spd. trans.....
The relay in the panel behind batteries do fail on with ign. switch off.
If trans light works, and if relay fails on....light will be on with ign. switch off.

 

[Bootkick]

I’m dealing with a battery draw as well. I have been following the alternator diagnostics in the tech manual. I found my alternator is getting power even when the ign is off. Further test in the diagnostics manual determined that the relay in the pcb is faulty. I just replaced less than 60 days ago! I think because my voltage regulator is bad and letting my voltage go up to 34 volts that it fried my new pcb. Now i need another pcb and a 60 amp alternator. Im hoping someone can guide me to an economical source for these items. My hummer is a M998 A-1… (I think). I’ve attached a pic of my alternator.

 

[Bootkick]

I failed to mention my hummer is a 1994 model.