TM 9-2350-277-20-1
COOLANT HEATER MALFUNCTIONSContinued
0089 00
4Y
1. Does HEATER ON indicator come on in less than 3 minutes?
YES
NO
GO TO GY (PAGE 0089 00-9)
5Y
1. Turn HEATER SWITCH to ON. Do not stop at OFF position.
2. Do blower and pump stay ON?
YES
NO
5YN
1. Replace heater ON/OFF/START
switch. See task: Repair heater
control box (WP 0737 00).
2. Verify no faults found.
6Y
1. Feel exhaust temperature.
2. Does heater continue to produce hot air for 10 minutes?
YES
NO
6YN
1. Shut off heater (see your -10).
2. Replace heater (WP 0728 00).
3. Verify no faults found.
7Y
NOTE
Heater will shut off prematurely if air inlet temperature is
60 degrees or above. This is normal.
1. Run heater on HI for 10 minutes.
2. Does heater continue producing hot air?
YES
NO
7YN
1. Shut off heater (see your -10).
2. Replace heater (WP 0728 00).
3. Verify no faults found.
8Y
1. Turn HEATER SWITCH to OFF.
2. Does blower remain on?
YES
NO
8YN
1. Heater does not purge.
2. Replace heater (WP 0728 00).
3. Verify no faults found.
9Y
1. Listen to heater until coolant pump and blower shut off.
2. Do coolant pump and blower shut off in less than 5 minutes?
YES
NO
9YN
1. Faulty heater flame detector switch.
2. Replace flame detector switch
(WP 0734 00).
3. Verify no faults found.
0089 00-2