Military Vehicle Repair: 24volt gauge, m1009, m1008

Question
I have a 24volt gauge from a M1008.  Is there a way to install it in my 1985 M1009 even though my Blazer did not come with the gauge from the factory?  From the electrical diagram, it looks like it grounds to the bus bar but I don't see where the + side goes.  Thanks Joe

Answer
You are correct...one side connects to ground.
The other connects to 24 volts, but through a relay, controlled by the 12 volt ignition circuit.
You could connect it directly to 24 volts, but it would measure voltage continuously, and eventually draw the battery down. That is the purpose for the relay.
The following will help wire in a relay.


http://www.the12volt.com/relays/relays.asp

Van