Table 156. The following conditions will turn the Fan ON for Illustration 66

209

TM 9-2320-312-24-2

Troubleshooting Section

Table 156

The following conditions will turn the Fan ON for Illustration 66.

Circuit

Condition that will turn the Fan ON

Coolant temperature sensor

The coolant temperature is greater than 96 C (205 F).

A diagnostic code for the coolant temperature sensor is

active.

Exhaust brake

The "Fan with Exhaust Brake ON" parameter is programmed

to "YES".

The exhaust brake is on at least two seconds.

OEM installed A/C control unit

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

to a value above 0 seconds.

The A/C control unit circuit is open.

The external timer is counting or the ECM timer is counting.

The engine rpm is greater than 2750 rpm.

The engine is cranking. The engine has been running two

seconds or the ignition key is on the ON position and the

engine off.

Air inlet temperature sensor

The temperature in the air inlet manifold is greater than 87 C

(189 F).

The temperature in the air inlet manifold is greater than 72 C

(162 F) while the boost pressure is greater than 70 kPa

(10 psi).

OEM installed manual fan override switch

There is an open circuit in the switch or the switch is on.

OEM installed cooling fan air solenoid valve

Open solenoid circuit

Circuit breaker for the cooling fan

Tripped breaker or open circuit

Dedicated PTO on/off switch

The "PTO Configuration" is programmed.

The "PTO Activates Cooling Fan" is programmed.

There is a short circuit in the switch or the switch is on.

g00766689

Illustration 67

This schematic represents the on/off fan with a normally closed relay and the A/C high pressure switch that is not connected to the ECM input.