Proheat M80 - Manual (Page 68)

PROHEAT G-I PCM SERVICE MANUAL 4-37
MOTOR Diagnostic Code 12
Indicates that an over-load fault is detected in precheck or during operation.
Troubleshoot the Motor diagnostic code based on:
1. Motor – mechanical.
2. Motor or G-I PCM – electrical.
Test Procedure – Motor mechanical function:
a) Disconnect all harnesses at the G-I PCM.
b) Disconnect the fuel supply line.
c) Remove blower housing (2) screws and blower housing. Look at blower
housing and blower for any rubbing marks.
If blower housing/blower rubbing is observed. Replace blower as it may
have warped.
d) By hand, rotate the blower and feel for mechanical binding.
If mechanical interference is felt, isolate the Motor from the Fuel Supply
Pump and Air Compressor by removing the Motor. Go to Motor
replacement, page 4-25.
If the Motor spins freely and there are no obvious mechanical problems,
check the Motor/G-I PCM electrical operation. Go to Test Procedure – G-I
PCM Motor output voltage.
Test Procedure – G-I PCM Motor output voltage:
a) Disconnect the Motor connector at the G-I PCM.
b) Reconnect the power and switch harnesses at the G-I PCM.
c) Switch the PROHEAT on.
If Motor diagnostic code is still indicated, G-I PCM is faulty. Go to G-I PCM
replacement, page 4-41.
If Motor diagnostic code is no longer indicated, Motor is faulty. Go to
Motor replacement, page 4-25.
4.1.13
(12 Flashes)
Figure 4-43: Motor Mechanical Check
COOLANT PUMP
SWITCH INPUT
TEMP SENSOR 1
POWER
FUEL INLET
BLOWER
NOTICE
All plugs/harnesses must be rein-
stalled into the Proheat Control
Module (G-I PCM) before heater goes
back into service.