I picked up an isolator. I know that basically I run each battery power to separate terminals on the isolator, and then the alternator to another terminal on the isolator, but the instructions mention something about hooking up a signal wire or some other wire from the alternator harness to another terminal on the isolator. Is this necessary?

It's just a unit I picked up from Napa.

 

anyone?

 

Are you sure it's not a wire that goes into the cab to select which batteries are used/charged?

I also think it could be a wire so when the alternator is on, the isolator charges both, but when the alternator is off (car off) the batteries are completely isolated. Just shootin out ideas here, never installed one before but have read up some on the topic

I think there's some info in the YT wiki, and the tech section about battery isolators.

 

Search for "dual batteries"

 

some people used high voltage relay with success.

 

Likely that is a sense wire for the alternator voltage regulator. If so, that is what lets the regulator "see" the battery voltage (vs. the battery + isolator-voltage-drop). If that is the case, then likely it is a good idea to connect it.

 

I think that's what it is. Any idea on what wire it connects to on the alternator harness?

 

I'm looking at my intructions for my isolator. Use your voltmeter and find a wire from the harness that show's 12 volts with the key turned (ignition).

 

Can it be run initially without this?