TM 9-2320-387-24-l
ENGINE COOLING
L
KNOWN INFO
FAN BLADES OK
SERPENTINE
BELT OK
FAN DRIVE OK
POSSIBLE
PROBLEMS
FAN WIRING
TIME-DELAY
MODULE
CONTROL VALVE
FAN TEMPERATURE
SWITCH
PCB
KNOWN INFO
FAN BLADES OK
SERPENTINE
BELT OK
DRIVE ENGAGES
POSSIBLE
PROBLEMS
FAN WIRING
TIME-DELAY MODULE
CONTROL VALVE
PCE
KNOWN INFO
=AN OK
SERPENTINE BELT OK
FAN ENGAGES AND
DISENGAGES
POSSIBLE
PROBLEMS
FAN WIRING
TIME-DELAY
MODULE
FAN TEMPERATURE
SWITCH
DISCONNECT WIRE 458A FROM
THE FAN TEMPERATURE SWITCH,
JUMPER 458A TO 4588. DOES THE
FAN DISENGAGE?
TEST OPTIONS
1. STUICE-R TEST 91 (Page 2-508)
MEASURE THE CONTINUITY
THROUGH THE FAN TEMPERATURE
SWITCH. THE SWITCH SHOULD BE
OPEN AT TEMPERATURES ABOVE
215°F (102°C) AND CLOSED BELOW.
IS THE SWITCH OK?
DISCONNECT WIRE 4588 FROM THE
FAN TEMPERATURE SWITCH. WITH
THE ENGINE RUNNING, IS THE FAN
ENGAGED?
DIAGNOSTIC FLOWCHART
TEST OPTIONS
REASON FOR QUESTION
Disconnecting 4588 from the switch
simulates a hot engine.
_
REASON FOR QUESTION
Having battery voltage on 458A
simulates a cold engine.
I
2. MULTlMmR
REASON FOR QUESTION
To check the switch operation.
Ideally. check the switch for open
and closed operation.
