TM 5-3805-280-24-1
System Operational Checks
3 HEATER CIRCUIT CHECKS (MACHINES EQUIPPED WITH HEATER ONLY)
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Remove fuse block cover.
3a BLOWER MOTOR 20
YES: Fuse is OK.
AMP FUSE (F13)
CHECK
Remove fuse from fuse block.
NO: Replace fuse. If fuse
blows again, check for
Using ohmmeter, check fuse for continuity.
short.
Is continuity measured?
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YES: Go to next check.
3b HEATER BLOWER
MOTOR SWITCH (S4)
CHECK (MACHINES
NO: Replace heater
EQUIPPED WITH
blower motor switch.
HEATER ONLY)
T111030 UN07AUG97
Disconnect wire harness from heater blower motor switch.
Connect ohmmeter to brown wire in switch connector and positive terminal of heater
9031
blower motor.
10
5
Turn heater blower motor switch to Low speed. Does ohmmeter read approximately
7.6 ohms resistance?
Turn heater blower motor switch to Medium Low speed. Does ohmmeter read
approximately 3.7 ohms resistance?
Turn heater blower motor switch to Medium High speed. Does ohmmeter read
approximately 1.2 ohms resistance?
Turn heater blower motor switch to High speed. Does ohmmeter read a lower
resistance than 1.2 ohms?
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