Fire Suppression System: Service and Repair

FIRE SUPPRESSION SYSTEM DEPOWERING AND REPOWERING

Special Tool(s):

Special Tool(s)

Depowering Procedure

WARNING:
- The fire suppression system backup power supply must be depleted before lifting the vehicle or when repairing or replacing any of the following:
- fire suppression system components
- components located near the fire suppression manual switch
- fuel tank and components located near the fuel tank
- rear axle and components located near the rear axle

To deplete the backup power supply, disconnect the battery and wait at least 1 minute. Be sure to disconnect the auxiliary batteries and power supplies (if equipped). Failure to follow these instructions may result in personal injury.

- Always wear safety glasses when repairing a fire suppression system vehicle and when handling a fire suppressor. This will reduce the risk of injury in the event of an accidental deployment.
- To reduce the risk of accidental deployment, never probe the connectors on the fire suppressors. Failure to follow this instruction may result in personal injury.
- To reduce the risk of accidental deployment, do not use any memory saver devices. Failure to follow this instruction may result in personal injury.
- If the vehicle is equipped with a fire suppression system, be sure that nobody is under the vehicle or near the rear axle area when the battery is connected due to possibility of an accidental fire suppression system deployment. Failure to follow these instructions may result in personal injury.

NOTE:
- If a vehicle equipped with fire suppression system is positioned on a hoist, the fire suppression system must be depowered.
- The fire suppression system indicator lamp illuminates when the fire suppression module (FSM) fuse is removed and the ignition switch is ON. This is normal operation and does not indicate a fire suppression system fault.
- The fire suppression system must be fully operational and free of faults before releasing the vehicle to the customer.

1. Turn all vehicle accessories OFF.
2. Turn the ignition lock cylinder to the OFF position.
3. Remove the central junction box (CJB) fuse 33 (10A).
4. Turn the ignition lock cylinder to the ON position and visually monitor the fire suppression system indicator for at least 30 seconds. The fire suppression system indicator will remain lit continuously (no flashing) if the correct FSM fuse has been removed. If the fire suppression system indicator does not remain lit continuously, remove the correct FSM fuse before proceeding to the next step.
5. Turn the ignition lock cylinder to the OFF position.

6. NOTE: If the battery voltage is required for diagnostics procedures, the battery must be connected without installing the FSM fuse.

Disconnect the battery and wait at least one minute.

Repowering Procedure
1. Install the CJB fuse 33 (10A) to the CJB and close the cover.

2. NOTE: This step is not required if the battery was connected after depowering procedure.

Connect the battery.

3. Prove out the fire suppression system as follows:

Turn the ignition lock cylinder from the OFF to the ON position and visually monitor the fire suppression system indicator. The fire suppression system indicator will light continuously for approximately six seconds and then turn off. If a fire suppression system fault is present, the fire suppression system indicator will:
- fail to light.
- remain lit continuously.
- flash.

The flashing might not occur until approximately 30 seconds after the ignition lock cylinder has been turned from the OFF to the ON position. This is the time required for the fire suppression module to complete the testing of the fire suppression system. If this occurs, the fire suppression system fault discovered must be diagnosed and repaired.

Clear all continuous DTCs from the fire suppression module using a diagnostic tool.