TROUBLESHOOTING
STEP
INSPECTION ACTION
*3
INSPECT WIRING HARNESS BETWEEN
CLIMATE CONTROL UNIT AND AIR INTAKE
ACTUATOR FOR SHORT TO GROUND
• Is there continuity between following climate
control unit connector (16-pin) terminals and
ground?
— Terminal 2B
— Terminal 2M
Yes Go to next step.
No
Repair wiring harness between climate control
unit and air intake actuator, then go to Step 9.
*4 INSPECT WIRING HARNESS BETWEEN
CLIMATE CONTROL UNIT AND AIR INTAKE
ACTUATOR FOR SHORT TO B+
• Tum ignition switch to ON position.
• Test voltage at climate control unit connector
(16-pin) terminals 2B and 2M.
• Is voltage approximately 12 V?
Yes
Go to next step.
No
Repair wiring harness between climate control
unit and air intake actuator, then go to Step 9.
5
INSPECT AIR INTAKE ACTUATOR
• Inspect air intake actuator.
• Is it okay?
Yes
Replace climate control unit, then go to Step 9.
No
Replace air intake actuator, then go to Step 9.
6
INSPECT BLOWER UNIT AIR INTAKE
ACTUATOR LINK AND CRANK
• Is there grease on air intake actuator link and
crank?
Yes
Go to next step.
No Apply grease, then go to Step 9.
7 INSPECT BLOWER UNIT AIR INTAKE DOOR
• Is there any foreign material or obstructions in
blower unit air intake door?
Yes
Remove material/obstruction, then go to Step 9.
No
Go to next step.
8
VERIFY THAT BLOWER UNIT AIR INTAKE
DOOR IS POSITIONED SECURELY AND
PROPERLY
• Is blower unit air intake door securely and
properly positioned?
Yes
Check air intake door for cracks or damage, then
go to next step.
No Install air intake door securely in proper position,
then go to next step.
9
CONFIRM THAT MALFUNCTION SYMPTOMS
DO NOT RECUR AFTER REPAIR
• Does air intake mode change when operating
air intake selector switch?
Yes
Troubleshooting completed. Explain repairs to
customer.
No
Recheck malfunction symptoms, then repeat from
Step 1 if malfunction recurs.
NO. 8 NO TEMPERATURE CONTROL
8
No temperature control.
DESCRIPTION • Temperature does not change when operating temperature control lever.
POSSIBLE
CAUSE
• Air mix actuator (+5 V signal) system malfunction (Steps 3-7, 10)
• Climate control unit (potentiometer GND signal) system malfunction (Steps 8,9)
• Air mix actuator (potentiometer input signal) system malfunction (Steps 11-13)
• Air mix actuator (potentiometer GND signal, motor drive signal) system malfunction (Step 14)
• Malfunction in air mix actuator system (Steps 15,16)
• Malfunction in heater unit air mix door (Steps 17,18)
Diagnostic procedure
• When performing an asterisked (*) troubleshooting inspection, shake the wiring harness and connectors while
doing the inspection to discover whether poor contact points are the cause of any intermittent malfunctions. If
there is a problem, check to make sure connectors, terminals and wiring harness are connected correctly and
undamaged.
STEP
INSPECTION
ACTION
1 INSPECT COOLANT TEMPERATURE
• Is coolant sufficiently warmed up?
Yes Go to next step.
No Warm engine up, then go to Step 19.
2
CHECK CIRCUITS COMMON TO BOTH AIR
MIX ACTUATOR AND AIRFLOW MODE
ACTUATOR
• Does airflow mode change when operating
airflow mode selector switch?
Yes Go to Step 10.
No
Go to next step.
U-28
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