Installing a masterswitch

heat is resistance....

 

Have you checked your batteries to see if one or more may be dead? I would also check the connections to make sure they are wired correctly.

 

'lil hijacking here... G/man, sending you a pm

 

A short could be anywhere also could be one of the battery's shorted inside pulling down the other battery's

 

You first want to clean every connection on the batteries, frame, alternator, and starter, Disconnect all the batteries and use a 10 amp regulated charger, take them all to a full charge, leave them overnight and check the voltage they should all be above 12,6 if not you have a problem there.
Battery drain can be a lot of things the easiest to check is the alternator not shutting down, when you shut off the truck take a wrench and put it up to the alternator pulley if it is attracted that is the problem.
If you have warm batteries and cold batteries the cold ones, are the problem. Connections are the opposite.

 

If the bad battery is starting to short out, I guarantee you it will not be cold!

 

When a battery shorts out it is not a slow process it will melt that section out quickly you are talking about a lot of amperage, discharging in a hurry, and the lead melts quick. They will blow up, or just make an open connection.