Cooling Fan Off Conditions

197

TM 9-2320-312-24-2

Troubleshooting Section

The inlet manifold air temperature is greater than

Operation of the cooling fan control can be

controlled independently of the ECM. The OEM

72 C (162 F) while the boost pressure is greater

installed air conditioning high pressure switch may

than 70 kPa (10 psi).

be used for independent cooling fan control. A cab

The manual fan override switch is on.

mounted override switch in the solenoid circuit can

also operate the cooling fan.

The "Fan with Exhaust Brake ON" is programmed

to "YES" and the exhaust brake has been on at

least two seconds.

The "A/C Switch Fan On-Time" is programmed

to a value above 0 and the A/C high pressure

switch is open.

The ECM is counting after the A/C high pressure

switch has closed.

The "PTO Activates Cooling Fan" parameter is

programmed to "Continuous" and the PTO on/off

switch is on.

The "A/C Fan Request Switch" is programmed to

"J1/P1:41" or "J1/P1:62" and the A/C compressor

clutch is activated.

The last five items in the previous list are dependent

upon the programming of the Customer Parameters.

Note: The ECM will turn off the cooling fan for 10

seconds during engine shutdown.

Cooling Fan Off Conditions

The cooling fan will be turned off by the ECM if

engine rpm exceeds 2800 rpm or when all the

following circumstances are met:

The coolant temperature is less than 92 C

(198 F).

The fan has been on for at least 30 seconds.

The inlet manifold air temperature is less than

53 C (127 F).

The strategy for the exhaust brake is not active

and the "Fan with Exhaust Brake ON" parameter

is programmed to "YES".

The A/C high pressure switch is not active.

The PTO on/off switch is in the OFF position and

the "PTO Activates Cooling Fan" parameter is

programmed to "Continious".

The A/C compressor clutch is not active.

The manual fan override switch is off.

The Cooling Fan Control can be Operated

Independently of the ECM.