A/c-Heater System: Overview Mazda MX-5 NB

DESCRIPTION

Blower case, mounted under right side of instrument panel, contains blower motor and fresh/recirculated air door. Evaporator case, to left of blower case, contains evaporator, evaporator thermoswitch and expansion valve. (Схема №4) Heater case, located next to evaporator case, contains heater core, airflow mode door and air-mix (temperature blend) door.

OPERATION

Air conditioning compressor clutch circuit is completed when A/C relay is energized and pressure switch is closed. The A/C relay is energized when Powertrain Control Module (PCM) grounds relay circuit. The A/C relay is energized with evaporator thermoswitch closed, A/C and blower switches on, and engine load not excessive. Condenser fan comes on when condenser fan relay is energized.

Blower resistor determines blower speed. With blower switch in highest position, blower motor circuit has the least resistance. As blower switch is moved to other positions, resistance is increased. Blower motor then operates at slower speeds depending on resistance.

Vehicle can be equipped with either lever-type or push-button control panel option. On lever-type control panel, all doors are controlled manually from control panel by cables. On push-button control panel, airflow mode and fresh/recirculated air doors are controlled by electric actuators, while temperature blend door is cable actuated.

NOISE DURING A/C OPERATION

1. Start engine. Turn A/C and blower motor switches on. If compressor vanes are making noise (buzzing, popping or beeping), go to step 5 . If compressor vanes are not making noise, go to next step.
2. If compressor is slipping (squeaking or whirling), go to step 13 . If compressor is not slipping, go to next step.
3. If compressor has interference noise (rattling or vibrating), go to step 17 . If noise is not interference, go to next step.
4. Turn ignition off. Turn A/C and blower motor switches off. Turn ignition on. Turn A/C switch on and listen for compressor clutch engaging (clicking). If compressor clutch engages, system is okay. If compressor clutch does not engage, check and adjust compressor clutch clearance. Clearance should be .014-.025" (.35-.65 mm).
5. Turn A/C switch off. Start engine. Turn A/C and blower motor switches on. Note length of time, after A/C is turned on, noise exists. If noise exists for less than 3 seconds, condition is normal. If noise exists for more than 3 seconds, go to next step.
6. Check engine idle speed. If engine idle speed is okay, go to next step. If engine idle speed is incorrect, adjust as necessary and retest system.
7. Check refrigerant charge. See «REFRIGERANT CHARGE CHECK»(ref-338-S07444725512000030800000) . If refrigerant charge is okay, go to step 9 . If refrigerant charge is not okay, go to next step.
8. Check A/C cooling lines for cracks or leaks. Repair or replace as necessary. If system leaks exist, replace receiver-drier and retest system. If cooling lines are okay, evacuate, recharge and retest system.
9. Turn ignition off. Evacuate refrigerant from system. Remove cooling line from compressor and add .8 fl. oz. of Denso Oil 9. Reinstall cooling line. Recharge system. Start engine and turn A/C switch on. If compressor noise still exists, go to next step. If compressor noise does not exist, adding oil corrected problem.
10. Turn ignition off. Evacuate refrigerant from system. Remove compressor. See «COMPRESSOR»(ref-338-S25843069232000030800000) under REMOVAL & INSTALLATION. Drain oil from compressor. Check oil for metal particles. If metal particles do not exist in oil, go to next step. If metal particles exist in oil, replace compressor. Recharge refrigerant and retest system.
11. If compressor oil is mixed with water, replace A/C system. If compressor oil is not mixed with water, go to next step.
12. If compressor oil is darker than normal and contains aluminum particles, replace compressor and receiver-drier and retest system. If oil is normal color with no contaminants, system is okay. Recharge and retest system.
13. If noise occurs immediately after compressor is stopped, replace compressor. If noise does not occur immediately after compressor is stopped, go to next step.
14. Check drive belt adjustment. See «SPECIFICATIONS»(ref-338-S13884198182000030800000) table. Adjust if necessary and retest system. If adjustment is okay, go to next step.
15. Check drive belt for damage, cracks or contamination. Repair or replace as necessary and retest system. If drive belt is okay, go to next step.
16. Inspect compressor clutch for wear, damage or incorrect adjustment. Repair or replace as necessary. If compressor clutch is okay, replace compressor and retest system.
17. Check compressor for correct installation. Repair as necessary. Check cooling lines for loose or damaged securing clips. Repair or replace as necessary and retest system.