3-23. EMERGENCY FAN CLUTCH OVERRIDE
The radiator fan in M998 series vehicles normally activates when engine temperature exceeds 220°F
(104°C) and deactivates when engine temperature drops to 190°F (88°C). If overheating occurs in an
emergency situation, this procedure will ensure continuous fan operation.
Raise and secure hood (para. 3-8).
Stop engine (para. 2-12) prior to disconnecting time delay module.
Disconnect time delay module connector (1) from control valve connector (2).
Start engine (para. 2-10).
Check fan for continuous operation. If fan is not operating continuously, stop engine and notify unit
Lower and secure hood (para. 3-10).
Allow engine to cool at idle until engine temperature lowers to normal operating temperature of 190°-
Proceed to unit maintenance with vehicle. Make certain unit maintenance is notified of emergency
service performed on vehicle.