Proheat X45–School Bus - Manual (Page 93)

PROHEAT INSTALLATION & SERVICE 5-36
Fuse Blown Test Procedure
with Power Connected and
PROHEAT Switched “OFF”
Check for correct battery polarity
Replace PCM Reconnect Internal Wire Harness
(18 Pin Connector)
Yes No
Remove Fuse
Replace Fuse
(15 amp only)
Does
Fuse
Blow?
Replace
Internal
Wire Harness
Reconnect Components
One at a time
Yes No
Does
Fuse
Blow?
Check Component as per
Troubleshooting Guide
Component OK
Yes No
Does
Fuse
Blow?
Disconnect all components from
Internal Wire Harness
(10 Connections) (See NOTE)
Reconnect Switch Harness
Yes No
Does
Fuse
Blow?
Check Switch Harness
and Connections
for Short Circuit
Harness OK
Yes No
Does
Fuse
Blow?
Disconnect from PCM:
• Internal Wire Harness
(18 Pin Connector)
• Switch Harness
NOTE: Ensure positive wire from
the PCM to the ignition coil
does not ground.
NOTE: A short circuit in the sleeper
fan outlet and hour meter
(auxiliary output) harness
will not blow the fuse. An
error will be indicated on
the PCM. This will not shut
the heater down.
Figure 5-28 Blown Fuse Test Procedure Flow Chart