Most Tahoe PPVs come with auxiliary battery option (Pro Code 6A6, 5W4 or 9C1), which is part of PPV package. Based on GM published electric circuit schematic, auxiliary battery only supplies power to police add-on electric gears which will be installed by an aftermarket upfitter before Tahoe being delivered to police department.
From 2015 - 2020 model, to preserve the primary battery power, the front engine bay installed auxiliary battery is connected to an isolator relay controlled by an ignition signal (Pro Code 5W4). When the engine is NOT running or the engine is cranking, the auxiliary battery supplies electric power to its designated loads without charging; when the engine is running, the isolator relay is closed and the the auxiliary battery connects to primary battery parallelly and gets charging. The isolator relay is located next to the brake vacuum boost.
From 2021 & up, the rear cargo area installed auxiliary battery is connected to an isolator relay controlled by an ignition signal (Pro Code 9C1). The isolator relay is located right above auxiliary battery.
Before a Tahoe PPV is decommissioned and back to civilian version, most police electric gears are removed. So, the auxiliary battery becomes no electric load, stays alone and a heavy cargo on the truck.
After you get your decommissioned Tahoe PPV, how do you deal with that auxiliary battery? Connect it to primary battery parallelly by by-passing the isolator relay or connect some electric devices to the auxiliary battery, like a trailer?
(From 2007 - 2014 Tahoe PPV had its Auxiliary Battery connected to primary battery parallelly without an isolator relay from GM factory (Pro code 6A6), as a matter of factor, both batteries run like one. So this original setup is excluded in this posting.)
2015 - 2020 Aux Battery Isolator Relay Location
2021 & Up Aux Battery Isolator Relay Location
From 2015 - 2020 model, to preserve the primary battery power, the front engine bay installed auxiliary battery is connected to an isolator relay controlled by an ignition signal (Pro Code 5W4). When the engine is NOT running or the engine is cranking, the auxiliary battery supplies electric power to its designated loads without charging; when the engine is running, the isolator relay is closed and the the auxiliary battery connects to primary battery parallelly and gets charging. The isolator relay is located next to the brake vacuum boost.
From 2021 & up, the rear cargo area installed auxiliary battery is connected to an isolator relay controlled by an ignition signal (Pro Code 9C1). The isolator relay is located right above auxiliary battery.
Before a Tahoe PPV is decommissioned and back to civilian version, most police electric gears are removed. So, the auxiliary battery becomes no electric load, stays alone and a heavy cargo on the truck.
After you get your decommissioned Tahoe PPV, how do you deal with that auxiliary battery? Connect it to primary battery parallelly by by-passing the isolator relay or connect some electric devices to the auxiliary battery, like a trailer?
(From 2007 - 2014 Tahoe PPV had its Auxiliary Battery connected to primary battery parallelly without an isolator relay from GM factory (Pro code 6A6), as a matter of factor, both batteries run like one. So this original setup is excluded in this posting.)
2015 - 2020 Aux Battery Isolator Relay Location
2021 & Up Aux Battery Isolator Relay Location
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