Idiot (me) needs electrical help

[Goatnut]

When I pull the negative battery cable and test between the neg. post and the block I am seeing a draw of 9volts. I'm sure it would be a full 12+ if the battery were fully charged. This was a brand new battery installed last night and it was below 10 volts this morning and again would not start the car. I checked at the fuses and see no power going across the fuses.

This all happened after I had changed the alternator, figuring it was bad and why the first battery went south. I can jump the car and pull the neg battery cable and the car will run for just a few second then it will die making me think the alternator is ...suspect. When I jump the car it is only charging at about 12 volts. I expected High 13's to 14+.

It seems as if the new alt. is not working and I have a major short somewhere. I am uncomfortable working with the electrical system and really need some advice as to where and how I can isolate the problems.

This is the wife's daily driver, her '72 Lemans, so any help getting this fixed would be greatly appreciated.

Thanks,
Scott

[Niessen]

Don't forget about the voltage regulator. Get a Wells VR715 (or equivalent) as they're solid state. For under $20 it's worth a try??

Just realized that the 72 might be internal reg? Oops.

[HOTROD64-STOCK69]

If you put a screw driver on the round plate(rear bearing housing) at the back of the alternator when the engine is running and it is magnatized to the the cover then the alternator is working. The battery could have a shorted cell. Hope this helps. Mike

[Realdeal]

Mike,

Where did you learn all of this stuff? Boy, you really come up with some good suggestions.

Realdeal