Fresh Air Intake View; Cj Service Diagnosis - Jeep 1979 CJ-5 Technical & Service Manual

HEATER 3D-3
Fig. 3D-3 Fresh Air Intake
Service Diagnosis
Condition
Possible Cause
Correction
FAN MOTOR (1) Blown fuse
(1) Replace fuse
WILL NOT RUN (2) Loose connection (2) Inspect and tighten
AT ANY SPEED (3) Poor ground (3) Clean and tighten
(4) Faulty switch (4) Replace switch
(5) Faulty m o t o r (5) Replace m o t o r
(6) Faulty resistor (6) Replace resistor
FAN MOTOR RUNS (1) Faulty switch
(1) Replace switch
AT ONE SPEED ONLY (2) Faulty resistor (2) Replace resistor
FAN RUNS BUT DOES (1) Intake blocked
(1) Clean intake
NOT CIRCULATE AIR (2) Fan n o t secured t o
(2) Tighten securely
motor shaft
Tighten securely
HEATER WILL NOT (1) Coolant does n o t reach (1) Check and replace
HEAT proper temperature
(1)
thermostat if necessary
(2) Heater core blocked (2) Flush or replace core
internally if necessary
(3) Heater core air-bound (3) Purge air from core
(4) Blend-air door n o t in (4) Adjust cable
proper position
WILL NOT D E F R O S T (1) Control cable adjustment (1) Adjust control cable
incorrect
(1) Adjust control cable
(2) Defroster hose damaged (2) Replace defroster hose
80587A