10si alternator
 

I'm having some electrical issues with my truck 72 k2500 350 4 speed.
Left my lights on a few days ago . Battery was dead the next morning. Swapped a new battery. Alternator was reading in the low 14s. Got to work and the truck was dead when I got out. Got a jump and to the parts store. All they had in stock closest to my year was a 1980 Camaro alternator. 10si internally regulated. Swapped the wiring over and headed out. Charging at 13.5 and slowly climbing. Battery was at 11.23 this morning. Any ideas and how to track this down. It's slowly draining when off.

My alternator wiring harness also did not have a ground wire.

To change the wiring I ran the blue wiring to the number one spot on the alternator. Rant the number 2 spot to the battery stud. Tan the red wire to the battery stud. The white wire on the original harness is snipped and I ran a jumper from the brown to blue write on the old regulator plug. Did I miss something?

Re: 10si alternator
 

I'm a bit lost in the description but: Main lug goes to main lug. #2 on alternator should have 12V all the time. Some just jump it to the main lug. #1 on alternator goes to the light on the dash.

But I'm confused why you changed the alternator to internal regulator if you just left your lights on? Seems like something else is going on?

Re: 10si alternator
 

I left my lights on and it killed the battery. The next day my battery was dead so I had the alternator tested. It failed. The parts store only had a 10si in stock so I installed that. Now it drains my battery over night. Not sure why. With the 1&2 plugs hooked on it drain .01 bolts every second. I unplugged the 1&2 and the drain stops. Could I install a diode in the key on wire to stop the draw?

Re: 10si alternator
 

Here's a link to one of the many many threads on the conversion to internally regulated alternators (10si or 12si).

http://67-72chevytrucks.com/vboard/s...d.php?t=362957

Re: 10si alternator
 

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Re: 10si alternator
 

Thank you. I'll take a look at this.