If I disconnect the positive lead on one of my batteries, does that then make my system a 12 volt instead of a 24 volt? Or will it still fry the 12 volt system if I try to give them a jump?

 

Your system is 12V.

 

Not according to my owner's manual, with dual 12 volt bats, it seems like it would be 24 volt. It specifically warns jumping 12 volt cars. But you say it's still a 12 volt?

 

You can make 12, or 24 volts out of two 12 volt batteries depending on how you have them wired. Your truck is wired for 12 because the positive on batt A goes right to the positive on batt B and the same for the ground. If you were to take the Positive from batt A and connect it to the negative on batt B, that would give you a 24 volt system which I am pretty sure is not the case on a PSD.

 

Okay, thank you. The manual must have been warning of the "serial connection" that you described making it a 24 volt.

 

Disconnect the second battery and jump the other vehicle using that battery. That way, your charging system is isolated from the other vehicle and the worst you can do to your own vehicle is toast one battery.