Mazda 626 - No Air Conditioning System Functions Operate

TROUBLESHOOTING
NO. 2 NO AIR CONDITIONING SYSTEM FUNCTIONS OPERATE
2
No air conditioning system functions operate.
DESCRIPTION
None of the air conditioning system functions operate, or else climate control unit indicator light does
not work.
POSSIBLE
CAUSE
• Malfunction in climate control unit GND system (Step 2)
• Malfunction in climate control unit power system (Steps 3, 4)
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 CHECK TO SEE WHETHER MALFUNCTION IS
IN CLIMATE CONTROL UNIT GND SYSTEM OR
POWER SYSTEM
• Do all indicator lights for each switch on
climate control unit illuminate when ignition
switch is turned to ON position?
Yes
Go to next step.
No Go to Step 3.
*2
CHECK TO SEE WHETHER MALFUNCTION
(LACK OF CONTINUITY) IS IN CLIMATE CON
TROL UNIT OR WIRING HARNESS (BETWEEN
CLIMATE CONTROL UNIT AND GROUND)
• Turn ignition switch to LOCK position.
• Disconnect climate control unit connector
(12-pin).
• Is there continuity between climate control unit
connector (12-pin) terminal 1K (GND signal)
and ground?
Yes
Replace climate control unit, then go to Step 5.
No Repair wiring harness between climate control
unit and ground, then go to Step 5.
3 INSPECT CLIMATE CONTROL UNIT POWER
SUPPLY FUSES
• Are climate control unit power supply fuses
okay?
Yes Go to next step.
No Check for short to ground on blown fuse’s circuit.
Repair or replace as necessary.
Install appropriate amperage fuse.
*4 CHECK TO SEE WHETHER MALFUNCTION
(LACK OF CONTINUITY) IS IN CLIMATE
CONTROL UNIT OR WIRING HARNESS
(BETWEEN FUSE BLOCK AND CLIMATE
CONTROL UNIT)
• Turn ignition switch to ON position.
• Test voltage at following climate control unit
connector (12-pin) terminals.
— 1A (IG2 signal)
— 1G (B+ signal)
• Is voltage approximately 12 V?
Yes
Replace climate control unit, then go to next step.
No
Repair wiring harness between fuse block and
climate control unit, then go to next step.
5 CONFIRM THAT MALFUNCTION SYMPTOMS
DO NOT RECUR AFTER REPAIR
• Does A/C system operate correctly?
Yes Troubleshooting completed. Explain repairs to
customer.
No
Recheck malfunction symptoms, then repeat from
Step 1 if malfunction recurs.
U-20