Proheat X45–School Bus - Manual (Page 89)

PROHEAT INSTALLATION & SERVICE 5-32
A SLEEPER FAN diagnostic code indicates an electrical short in the sleeper
fan wiring harness, electrical connections or fan motor. This error will not
shut the heater down and heat to the engine will be maintained. An open
circuit will not display a diagnostic code.
NOTE: This error is only applicable to "Sleeper Fan" models. See page 4-2 for
model identification. If the PCM model is an "Aux Input" model and
this error is displayed, there is a fault with the PCM. Replace the PCM.
Symptom: Sleeper Heater fan not turning (code indicated)
Check: Sleeper Heater system
a) The wiring connections and polarity.
b) For an electrical short from the positive wire to the negative
wire. For an electrical short from the positive wire to the
chassis. Test sleeper heater fan. (See Test Procedure)
Sleeper Fan Troubleshooting (No code Indicated)
The following material covers the sleeper fan mechanical or electrical
problems that do not indicate a Code 13. Note that the sleeper fan is high
side switched.
Symptom: Sleeper Heater fan not turning (no code indicated)
Check: Sleeper Heater system
a) The wiring connections and polarity.
b) Test sleeper heater fan. (See Test Procedure)
Symptom: Sleeper Heater system has low air flow (no code indicated)
Check: Sleeper Heater system
a) Air ducting.
b) Use Test Procedure items (e) and (f) to determine if PROHEAT
is supplying enough power to drive the sleeper fan.
Test Procedure:
a) Disconnect sleeper fan harness.
b) Restart the PROHEAT, If there is still an error, replace the PCM.
c) Check for correct voltage at the sleeper fan output on the
PCM. (See wiring diagram on page 1-4 and page 1-5.)
d) Reconnect sleeper fan harness. Start the PROHEAT.
e) Check for voltage at the thermostat, isolator (if used) and the
sleeper fan motor. The power to the sleeper heater fan is
regulated by voltage in the PCM. It will read low when trying
to drive the sleeper fan.
f) Connect sleeper heater fan motor directly to a remote power
source of the rated voltage (12/24 Volts). Does the motor run?
13 Sleeper
Fan
NOTICE
The PROHEAT PCM sleeper fan
circuit has a one minute delay
during ignition. Power to open a
sleeper fan coolant valve must be
taken from another source such as
the wire for the Hour Meter (Auxiliary
Output). (See PROHEAT Wiring
Diagram page 1-4.)
SECTION 5. TROUBLESHOOTING & REPAIR