MAZDA MX-5 1994 Workshop Manual

TROUBLESHOOTING u Symptom: Condenser fan does not operate Normal operation of condenser fan The PCME controls the operation of the condenser fan and magnetic clutch, depending on engine load. (Refer to section F.) The condenser fan is supplied with battery positive voltage as follows: 1. The ACS and fan switch are turned on. 2. The PCME receives a signal that the ACS and fan switch are on and creates a ground circuit. 3. The A/C relay is magnetized and the contact is closed. 4. Battery positive voltage is applied to the condenser fan and the fan operates. Step 1 1. Turn the ignition switch to ON. 2. Measure the voltage at terminal A (B/Y) of the condenser fan connector. B+: Battery positive voltage Step 2 1. Disconnect the condenser fan connector. 2. Check for continuity between terminal B (B) of the con- denser fan connector and ground. Voltage B+ Other I GO to step 3 Action Go to Step 2 I continuity I Action I Step 3 1. Remove the condenser fan relay. 2. Apply battery positive voltage and check for continuity between the relay terminals. B+: Battery positive voltage Yes No Replace condenser fan Repair wiring harness (Condenser fan - GND) M: Continuity - - - 3. If correct, go to Step 4. 4. If not as specified, replace the condenser fan relay. 1 0 2 B+ Step 4 Check for continuity between terminal A (BN) of the con- denser fan connector and terminal C (BN) of the con- denser fan relay connector. I Continuity I Action 1 Repair wiring harness (Condenser fan relay - Fuse) B 0 GND I Repair wiring harness (Condenser fan - Condenser fan relay) I C 0 0 E 0 F 0 Gartner Banana

TROUBLESHOOTING I ltem 1 Symptom Symptom: lnsuff icient cooling No cooling Intermittent cooling Ill Bubbles present in sight glass u Immediately after air conditioner turned off, refrigerant in sight glass stavs clear I. When air conditioner turned off, re- frigerant foams, and then sight glass becomes clear No bubbles present in sight glass Step 1 Checking refrigerant charge 1. Run the engine at a fast idle. 2. Operate the air conditioner at maximum cooling for a few minutes. 3. Observe the sight glass to determine the amount of re- frigerant and the related action as shown below. Amount of refrigerant Action Insufficient refrigerant Too much or proper amount of refrig- erant Too much refrigerant Step 2 Checking refrigerant pressure 1. Connect the manifold gauge set. 2. Operate the engine at 1,500 rpm and set the air condi- tioner to maximum cooling. 3. Measure the refrigerant pressure. 1 Proper amount of refrigerant Normal pressure Low-pressure side: 0.1 5-4.24 MPa (1.5--2.5 kgf/cm2, 22--35 psi) High-pressure side: 1.38-1.56 MPa (1 4.0-1 6.0 kgf/cm2, 200-227 psi) Check refrigerant pressure, go to Step 2 Turn air conditioner off, and watch bubbles (Refer to Items 3 and 4) Check refrigerant pressure, go to Step 2 Refrigerant amount normal 4. If the pressures not as specified, refer to the chart on the next page and check the system. ,d Gartner Banana

TROUBLESHOOTING Case 1: Insufficient refrigerant Measured pressure Low-pressure side: 0.05-4.09 MPa (0.5--1.0 kgf/cm2, 8-1 4 psi) u High-pressure side: 0.69-498 MPa (7.0-1 0.0 kgflcm2, 100-142 psi) Condition Outlet air from vents not cold. Bubbles seen in sight glass. Step 1 1. Check for oil stains on the pipes, hoses and other parts. (Refer to illustration below.) 2. If oil staining is found at the connection of pipes or hoses, replace the O-ring; then evacuate, charge, and test the svstem. 3. If oil staining k not found, go to Step 2. Step 2 1. Check for leakage from the following connections with a gas leak tester. lnlet and outlet of condenser. lnlet and outlet of receiver drier. lnlet and outlet of A.C compressor. Sight glass. lnkt and outlet of cooling unit. 2. If leakage is evident, go to Step 3. 3. If leakage cannot be found, evacuate, charge, and test the system. (System OK, but refrigerant leaked gradually over time.) Step 3 L-/ 1. Check tightening torque of the connection where leak was detected. 2. If the connection is loose, tighten the connection to the specified torque; then evacuate, charge, and test system. 3. If the connection is properly tightened, replace the O-ring; then evacuate, charge, and test the system. Gartner Banana

TROUBLESHOOTING Case 2: Excessive refrigerant or insufficient condenser cooling Measured pressure Low-pressure side: 0.254.34 MPa (2.5--3.5 kgf/cm2, 3-9 psi) High-pressure side: 1.97-2.45 MPa (20.0-25.0 kgflcm*, 285--355 psi) Condition Outlet air from vents not cold. Note If the condenser fan does not operate when the air conditioner is operating, see "Condenser fan does not operate"; page U-9, before proceeding. Step 1 1. Make sure the condenser fan operates when the air con- ditioner is operating. If it does not operate, troubleshoot the condenser fan circuit (page U-9) before proceeding. 2. Check the condenser for bent fins or damage. Repair or replace if necessary. 3. If the condenser is OK, go to Step 2. Step 2 Verify that the refrigerant pressure is normal. Case 3: Air in system Measured pressure Low-pressure side: 0.254.29 MPa (2.5--3.0 kgflcmz, 36-42 psi) High-pressure side: 1.97-2.45 MPa (20.0-25.0 kgf/cm2, 285--355 psi) Condition Insufficient cooling. CAUSE ACTION 7 EVACUATE SYSTEM Step 1 Discharge the refrigerant system. Step 2 Evacuate the system to remove all air from it. (Refer to page U-25.) Step 3 Charge the system with refrigerant. (Refer to page U-25.) Step 4 After charging, measure the refrigerant pressure. (Refer to page U-29.) .- Step 5 If low- and high-pressure sides are still too high, replace the receiver drier. Gartner Banana

TROUBLESHOOTING Case 4: Moisture in system Measured pressure Low-pressure side: Vacuum High-pressure side: 0.69-4.98 MPa (7.O-lO.O kgf/cm2, 100-1 42 psi) Condition Insufficient cooling. (Moisture in refrigeration system freezes in expansion vaive and causes temporary block- ing. After time, ice melts and condition returns to normal.) CAUSE n MOISTURE IN I SYSTEM le ACTION EVACUATE SYSTEM Step 1 Discharge the refrigerant system. Step 2 Evacuate the system to remove all air and moisture from it. (Refer to page U-25.) Step 3 Charge the system with refrigerant. (Refer to page U-25.) Step 4 After charging, measure the refrigerant pressure. (Refer to page U-29.) Step 5 if low- and high-pressure sides are still too low, replace the receiver drier. Case 5: No refrigerant circulation Measured pressure Low-pressure side: Vacuum ~ighLpressure side: 0.50--0.58 MPa (5.0--6.0 kgf/cm2, 72-45 psi) Condition b Refrigerant flow obstructed by moisture or dirt, causing freezing or blockage of expansion valve. CAUSE ACTION MOISTURE IN CAUSE ACTION Step 1 Turn off the air conditioner for about 10 minutes. Turn on the air conditioner to determine whether the biockage is due to moisture or dirt. a) If caused by moisture System will operate normally after being off for 10 min- utes. (Ice melts and relieves blockage.) Refer to "Moisture in system"; page U-13. b) If caused by dirt System remains abnormal after being off 10 minutes. Go to Step 2. DIRT IN SYSTEM Step 2 1. Remove the expansion valve. (Refer to page U-31.) 2. Blow out the dirt with compressed air. 3. If unable to remove the dirt, replace the expansion valve. 4. Evacuate, charge, and test the system. CLEAN OR REPLACE EXPANSION VALVE Gartner Banana

u TROUBLESHOOTING Case 6: Expansion valve stuck open Measured pressure Low-pressure side: 0.30-0.39 MPa {3.0-4.0 kgf/cm2, 43-56 psi) High-pressure side: 1.97-2.45 MPa (20.0-25.0 kgf/cm2, 285-355 psi) Condition Insufficient cooling. CAUSE ACTION 7 m EXPANSION REPLACE / VALWEiUCK I *I EXPANSION VALVE Case 7: Faulty AIC compressor Measured pressure 1. Check whether there is frost or heavy dew on the suction pipe (between cooling unit and AIC compressor). 2. If neither is found, refer to "Excessive refrigerant or insuf- ficient condenser cooling"; page U-12. 3. If either is found, replace the expansion valve. (Refer to page U-31.) LOW-pressure side: 0.4-0.5 MPa (4.0-6.0 kgf/cm2, 57-85 psi) High-pressure side: 0.69-0.98 MPa (7.0-10.0 kgflcm2, 100-1 42 psi) Condition No cooling. I 1 Remedy CAUSE ACTION MOISTURE IN 1. Run ihe engine at a first idle. 2. Verify that the magnetic clutch is on when the ACS and fan switch are on. 3. If the magnetic clutch remains off, refer to "Magnetic clutch does not operate"; page U-7. Gartner Banana

HEATER u HEATER STRUCTURAL VIEW 1. Heater unit 45UOUX401 3. Heater control unit Removal 1 Installation ......... page U-16 Removal I lnstallation ......... page U-20 Disassembly / Assembly ...... page U-17 Disassembly l Assembly ...... page U-21 Inspection ................... page U-17 Inspection ................... page U-22 2. Blower unit Adjustment .................. page U-22 Removal 1 Installation ......... page U-18 4. Cooling unit Disassembly I Assembly ...... page U-19 Removal I Installation ......... page U-30 Inspection ................... page U-19 Disassembly / Assembly ...... page U-31 w Note Even in vehicles not equipped with NC, there is a cooling unit. If it is necessary to remove this unit to service the heater, then be sure to reinstall the cooling unit into its original position after servicing is complete. Gartner Banana

u HEATER HEATER UNIT Removal / Installation 1. Remove the dashboard. (Refer to section S.) 2. Remove the heater unit as shown in the figure. 3. Install in the reverse order of removal. 7.9-10.7 Nm (80-110 kgfcm, 69.5--95.4 In+bf] 1. Heater hose U-16 45UOUX4 2. Heater unit Gartner Banana

HEATER u Disassembly / Assembly Disassemble and assemble as shown in the figure. 1. Heater core 2. Air mix door 3. Airflow mode door Inspection Heater core 1. Check the heater core fins for blockage. 2. If the fins are clogged, clean them. 3. Check the fittings for cracks or other damage. Replace the heater core if necessary. Gartner Banana

u HEATER BLOWER UNIT Removal / Installation 1. Remove the glove compartment. (Refer to section S.) 2. Remove the blower unit as shown in the figure. 3. Install in the reverse order of removal. 7.910.7 Nm (80-110 kof cm, 69.5-95.4 Inlbf) 1. Blower unit U-18 Gartner Banana