ok so i just picked up a 79 12a its been siting for atleast 5 years...i put a new starter on it and cleaned the points up on it and draind the old gas put new gas in it and it started and runs... my question or problem is...i was cleaning it out and all of a suden the power just came on evan though the key was off and out...iv checked the conections to the ignition (unpluged them all and it still did it) fuses are all good...im lost....i can start it but i cant shut it off with out disconecting the battery...so im askin why is it doing that and how do i fix it????

 

I guess I would start looking for any wiring that does not appear to be stock. Look around the fusible links, and the coils first.

 

it has some randome unpluged conecters and cliped wiers but y would it just all of a suden do that i mein we had it running then shut it off about 3 mins latter it just turnd on

 

Ever see the Steven King movie " Christine " ? Sounds like you have one.

 

lol yea that might b exept the last owner is still alive lol

 

haunted fer sure

 

Download the 79 FSM from rotaryrefs.net and start studying the wiring diagrams. From you're description, repair will take an onsite visual inspection and comparison with the oem wiring to sort out your problem.

 

the site wont let me on it it said forbiden......is that the same diagram that is in the haynes manual ?

 

ok i think i have salved the problem it was the voltage regulater or so i think i have a new one coming tomarow ill know more then...if it isent that its somthin in the wiers going to it...

 

problem solved it was the voltage regulater...

 

Mine did this when I tried to convert it to internal VR alt, so check the VR itself.
Also to upgrade to the 81-85 alt would be a good idea if you can fing the write to convert the SA's to FB's alts.