Aux Battery Relay Switch - red wire cut???

[deserted]

Recently got a 2016 Tahoe with a winch and dual battery setup. It was an auctioned Sheriff's assist vehicle. All they left from the PPV equipment was the winch. Replacing batteries and while checking fuses noticed the red wire for the relay switch had been cut. Should this be connected to something? If not, does this mean the second battery is always isolated from the alternator, ingition system, etc.? Thanks!

 

[deserted]

Ah, it makes sense now... the driver's side battery runs the winch. The alternator is connected to the passenger side battery, and has the bank of Littel fuses. Still, what to do on the isolator relay switch?

 

[nyc7708ems]

If I remember correctly the relay switch allows the primary battery to charge the secondary one till a point then shuts it off. And the relay is setup if correctly can monitor secondary voltage. And the reason for the secondary battery was so all the up fit equipment like the winch, lights, sirens and radios wouldn’t drain the primary battery and could start the vehicle should there be a heavy draw on the secondary battery.