PREVOST H3-41 Maintenance Manual page 923

Problem/Symptom
HVAC condenser fans not
functioning in speed 1
HVAC condenser fans not
functioning in speed 2
Defroster fan is functioning
but no heat or cooling
available in the driver's area
The A/C compressor clutch
does not engage
SECTION 22: HEATING AND AIR CONDITIONING
Probable Causes
Module A49 (A54 on H3 VIP &
X3 VIP) is not powered or is
faulty
Circuit breaker CB7 (CB5 on X3
VIP) tripped
Seized bearing
Bad wiring
Module A46 is not powered or is
faulty
Bad wiring
Module A52 is not powered or is
faulty
PA1621 Maintenance Manual All Series | Revised February 2019
Actions
1. Check the Diagnostics menu of Driver
Information Display (DID). Select Fault
Diagnostics and Electrical System. The
message "No Response ModA49, Active"
indicates a power problem on the module.
(A CAN network problem would show the
same message but doesn't produce this
symptom).
2. Check / reset circuit breaker CB5 except:
X3 VIP check CB7
3. Check fuse F65 except :
H3 VIP check F67+F68
X3 VIP check F67
4. Probe gray connector on module to see if
it is powered.
1. Check / reset circuit breaker CB7
2. See HVAC condenser fans not
functioning & HVAC condenser fans
not functioning in speed 1 above.
1. Check the Diagnostics menu of Driver
Information Display (DID). Select Fault
Diagnostics and Electrical System. The
message "No Response ModA46, Active"
indicates a power problem on the module.
(A CAN network problem would show the
same message but doesn't produce these
symptoms).
2. Check / reset circuit breaker CB1(CB7 on
X3 VIP)
3. Check fuse F12V & F13 except X3 VIP
4. X3 VIP check fuse F65
5. Probe gray connector on module to see if
it is powered.
1. Check the Diagnostics menu of Driver
Information Display (DID). Select Fault
Diagnostics and Electrical System. The
message "No Response ModA52, Active"
indicates a power problem on the module.
(A CAN network problem would show the
same message but doesn't produce this
symptom).
2. Check / reset circuit breaker CB5
3. Check fuse F65
4. Probe gray connector on module to see if
it is powered.
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