Newly aquired m1009...wiring issues

[WalkingToFreedom402]

Hello, I recently purchased a M1009 & have begun tracing wires & reading Technical Manuals.

The previous owner only had the truck for a few months. He claims that the starter 'was acting up' so he replaced it. It hasn't ran since.
There are 2 wires which were clearly burnt up near the terminal block...one comes off of the rear battery negative cable & the other appears to head to the drivers side alternator.

I began by disconnecting & removing the starter to verify that it had a 24 v solenoid which it did. I left the starter unhooked & taped the leads for testing purposes. I installed 2 new batteries & rigged up fuses in case I had a short. I followed a battery diagram that I found on this site. I connected the rear battery positive, then the negative, then the positive on the front battery(which goes to the negative on the rear), then the front battery negative which is grounded to the block/frame. Neither fuse popped but within 15 seconds I saw smoke coming from one of the terminals & quickly disconnected it.

I would love some opinions on what the previous owner may have done incorrectly & any recommendations on which direction that I go with my troubleshooting.

I have spent some time reading posts on this forum...just looking for some guidance.

Thanks in advance.


PS: I should also include that it came with no batteries & that I comfirmed the trucks operation from another previous owner who did state that he had some sort of a drain on the batteries the entire time that he owned it.

 

[1986 M1031]

Off the top of my head sitting at work, I bet it is the alt that should not be grounded.

 

[dependable]

Maybe check condition of cable that feeds starter. Sloppy starter installation could have it hitting the heat shield or something. Sounds like there is a short somewhere.

 

[WalkingToFreedom402]

Thanks for the responses. I had not previously heard of 1 alternator being ungrounded....I will research that.
I am also going to look further into the condition of all of the cables. Thanks guys!

 

[cpf240]

Thanks for the responses. I had not previously heard of 1 alternator being ungrounded....I will research that.
I am also going to look further into the condition of all of the cables. Thanks guys!

In stock form, both alts are 'isolated ground' which means that the are not grounded through the case, as most alts are. In the case of GEN 1 - driver's side - there is a ground wire connected to the intake manifold and the ground stud on the alt. GEN 1 can be replaced with a standard alt. However, GEN 2 - passenger side - *MUST* be an isolated ground, as it uses the output of GEN 1 as its ground reference, which gets the 24v output from what is really a 12v alternator.