Proheat X45–School Bus - Manual (Page 88)

5-31 SECTION 5. TROUBLESHOOTING & REPAIR
Figure 5-25 Blower Test
MODEL CURRENT DRAW (Amps)
X45-12 .75 - 1.5 @ 12 Volts
X45-24 .5 - 1.0 @ 24 Volts
iii) Inspect internal harness wires going to blower. Ensure
that there is no chaffing or cuts that would provide a
blower motor ground short.
If internal harness is good condition, replace PCM
Symptom: Blower not running (no code indicated)
Fuse blown in PCM
Check: Blower function
a) Harness for pinched or abraded wires.
Positive lead must not short to ground.
b) Check motor for internal short.
(See Figure 5-25 and Test Procedure)
Symptom: Blower turning slowly (no code indicated)
Check: Blower function
a) For fan blade rubbing on housing.
b) For fan blade slipping on motor shaft.
Test Procedure:
a) Connect the blower to a power supply of the rated voltage.
Does it turn? If not, replace the blower.
b) Measure the blower motor resistance. Using a multimeter,
measure the resistance across the blower connector pins. If
resistance shows an open circuit or an internal short circuit,
then replace the blower assembly.
c) Measure blower current. Use test lead part #967921K as
described on Service Bulletin #967329 in Appendix.