Battery Disconnect - Dual 12 Volt Battery System

Courtesy of CHRYSLER GROUP, LLC

On this dual battery system the auxiliary battery ground cable connects to the main battery cable end (shown in generic illustration above) and grounds through the main battery ground cable connection to the body, chassis or engine (depending on vehicle). Therefore, simply disconnecting and isolating the main battery negative cable clamp from the main battery post will not isolate the auxiliary from the vehicle's electrical system. The auxiliary battery will still be grounded through it's connection to the main battery negative cable end. If both battery negative cables are not isolated it will result in the vehicle electrical system and Power Distribution Center (PDC) still having battery connection which can cause vehicle wiring damage or deployment of air bags on re-connection.

DUAL BATTERY DISCONNECT PROCEDURE: 

1. Turn the ignition off. Wait five minutes to allow the main modules to go to sleep.
2. Disconnect and isolate the supplemental (auxiliary) battery negative cable from the main battery negative cable end. This will disconnect and isolate the auxiliary battery ground.
3. The main battery ground can be disconnected by removing the main battery negative cable from the negative battery cable end, or by disconnecting the IBS connector, loosening the negative battery clamp nut and removing the negative battery cable end from the battery post. Either method will disconnect the main battery. Both batteries should be disconnected from the vehicle electrical system.
4. Measure the voltage at the PDC positive battery cable connection to verify the vehicle electrical system is powered down.
   NOTE:

   On some vehicles a small amount of voltage may be present (typically less than approximately 0.5 volts) due to capacitors is some modules still having voltage stored. Anything less than 1.0 volts should be safe.

DUAL BATTERY CONNECT PROCEDURE: 

1. Connect the main battery negative clamp to the post and tighten to the proper torque specifications, or connect the main battery negative cable to the negative cable clamp. Refer to TORQUE SPECIFICATIONS  . If the main battery negative cable is connected with a nut, install the nut and tighten to the proper torque specifications. Refer to TORQUE SPECIFICATIONS  .
2. Connect the IBS harness connector if disconnected.
3. Connect the auxiliary battery negative cable to the main battery negative cable clamp. If connected by a nut, install the nut and tighten to the proper torque specifications. Refer to TORQUE SPECIFICATIONS  .
   NOTE:

   Overtightening of the nuts connecting the negative cables to the IBS may cause damage to the IBS or break the stud.