1994 MAZDA MX-5 cooling

INDEX u AIR CONDITIONER 1. Cooling unit 5. Condenser fan relay ................... Removal 1 Installation ......... page U-30 Inspection page U-37 Disassembly I Assembly ...... page U-31 6. A/C compressor 2. Condenser Removal 1 Installation ......... page U-38 ...... Removal I Installation ......... page U-33 Disassembly I Assembly page U-41 3. Receiver drier 7. Magnetic clutch Removal I Installation ......... page U-33 Disassembly 1 Assembly ...... page U-39 4. AIC relay Inspection ................... page U-37 Gartner Banana

TROUBLESHOOTING u TROUBLESHOOTING GUIDE I Symptom Blower motor does not operate Reference page Below Magnetic clutch does not operate I U-7 Condenser fan does not operate e Symptom: Blower motor does not operate I U-9 Insufficient cooling No cooling Intermittent cooling Normal operation of blower motor Blower motor speed is controlled by the fan switch and a resistor in the blower unit. When the fan switch L is in the OFF position, the motor ground circuit is open and the blower motor does not operate. When the switch is in the first (Low) position, current flow from the blower motor is restricted by the three resis- tors in the resistor, and the blower motor turns at low speed. Changing the fan switch to the second (Mid), third (high), or fourth (Super-high) position causes the cir- cuit resistance to decrease, and the blower motor speed becomes correspondingly faster. I l U-10 (-1 (rn) I I I RESET BUTTON FUSE BLOCK Step 1 1. Check the circuit breaker. 2. If the reset button is not out, go to Step 2. 3. If the reset button is out, check for a short circuit in the harness. Repair as necessary; then depress the reset button to reset the circuit breaker. circuit breaker HEATER Step 2 1. Turn the ignition switch to ON. 2. Turn the fan switch to the fourth position. 3. Measure the voltage at the A terminal wire of the blower motor connector. B+: Battery positive voltage I Terminal I Voltage Action I Amperage 30A Location Fuse block A U-5 Bt Other Go to Step 3 Repair wiring harness (Circuit breaker - Blower motor) 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