1994 MAZDA MX-5 heater

OUTLINE T NO type relay I STOP Not in operation (No power supply) ax FLOW I STOP NC type relay NO switch In operation (Power supply) ELECTRICAL SYMBOLS Switches and Relays There is an NC (normally closed) and NO (normally open) indication for switches and relays that shows when no change of operation conditions has occurred. Relay Switch I w FLOW - Other Electrical Symbols - ax STOP FLOW NC switch FLOW STOP I I I I - FUSIBLE LINK e $1 VARIABLE RESISTOR + LIGHT TRANSISTOR HOLDER BOX FUSE 4 RESISTOR 1 T CONDENSER BATTERY 4) MOTOR 8 THERMISTOR SPEAKER I CIGARETTE LIGHTER I HEATER - - BODY GROUND t COIL, SOLENOID + DIODE I 25UOTX-010 Gartner Banana

T FUSE DESCRIPTION Main Fuse Block The main fuse block is located on the right side of the engine compartment and contains nine fuses and two relays. -1 Fuse Box Fuse block No.1 is located above the dead pedal of the driver side. The fuse box cover shows the speci- fied fuse locations. A circuit breaker is included in the fuse box to protect the heater blower motor circuit. Fuse block No.2 is located to the side of the battery in the trunk compartment. 45UOTX-016 REPLACEMENT Caution Determine and correct the cause of a burnt fuse before replacing it. If the fuse is replaced before doing this, it may burn again. Plate type 1. Disconnect the negative battery cable. 2. Replace the failed fuse with the fuse puller. 3. Reconnect the negative battery cable. Cartridge-type 80A fuse (Black) 1. Disconnect the negative battery cable. 2. Remove the fuse block mounting nuts, and remove the service cover. 3. Remove the fuse installation bolts, and pull out the fuse. 4. Install the new fuse and the fuse installation bolts. 5. Install the main fuse block. 6. Reconnect the negative battery cable. Gartner Banana

nia (i' [-I PACL LIGHT '-6 1.4k HEATER CDNTRCL CONTROL X3 SWITCH SWITCH ILLMI1UATIONS 1 -a? .ILLUMINATION LIGHTS WARNING I CRUISE CCNTQOL ILLVMINATION -0l PANEL LIGHT CONTROL SWITCH (I1 I 1-02 HEATER CONTROL SWITCH ILLGMINA~IONS (11 11-03 ASHTRAY ILLUMINATION (I) H-06 AT SELECT ILLUMINATION(II I -07 HAZARD WAWING AND RETRACTOFi SWITCH ILLUMINATION(II I-oz CRUISE CONTROL MAIN snITcn ILLWINATION (11 E-10 FRONT FOG LIGHT ANO REAR WIMOW DEFROSTER SUITCH ILLUMINATION (I) I Gartner Banana

REAR WINDOW DEFROSTER REAR WINDOW DEFROSTER STRUCTURAL VIEW 1. Rear window defroster L/ 2. Rear window defroster switch 3. Rear window defroster relay 4. Rear window defroster timer unit DESCRIPTION The rear window defroster switch is included in the heater control switch assembly. Gartner Banana

REAR WINDOW DEFROSTER T u Symptom: Rear window defroster does not operate. 9MUOTX-232 Step 1 1. Check the following fuses. I Fuse Amperage I Location I 2. If all the fuses are OK, go to Step 2. 3. If a fuse is burned out, replace it. Check and repair the wire harness, if necessary. R.DEF HEATER -- M: Continuity 20A 30A Step 2 1. Disconnect the rear window defroster relay. 2. Apply battery positive voltage and check for continuity between terminals of the relay. B+: Battery positive voltage 3. If correct install the rear window defroster relay and go to Step 3. 4. If not as specified, replace the rear window defroster relay. Fuse box No.2 Main fuse block Step 1 2 C Terminal D 0 GND B 0 B+ A 0 C 0 Gartner Banana

T REAR WINDOW DEFROSTER Step 3 1. Turn the ignition switch to on. 2. Turn the rear window defroster switch on. 3. Check the voltage at the terminal wires of the rear win- d dow defroster rday connector. B+: Battery positive voltage Terminal (uB) c (R) Step 4 Check if the heater operates in the first position. I Operation I Action I Voltage B+ other NG Repair wiring harness (Heater switch- Rear window defrostertimer unit) Action Check C terminal Repair wiring harness (HEATER fuse - Relav) B+ Other . , Go to Step 4 Go to Step 5 I Step 5 Check the voltage at the rear window defroster connec- tors. Check A terminal Repair wiring harness (DEFOG fuse - Relavl A (w) B+: Battery positive voltage B+ Other Terminal I Voltage I Action B+ I Check C terminal other If all above-mentioned parts are normal, replace the rear window defroster timer unit. Repair wiring harness (Defroster - Defroster timer unit) c (W) A (B) . B+ Other B+ Other Check A terminal Repair wiring harness (Relay- Defroster) Repair wiring harness (Defroster - GND) Repair defroster filament Gartner Banana

SRS AIR BAG SYSTEM T COMPONENT DESCRIPTION Component Air bag module Function Air bag system warning light Deploys air bag when current flows to integrated igniter Light illuminates or flashes if malfunction occurs in air bag system I EE with S-sensor, completes Circuit Clock spring I Ensures uninterrupted electrical connec- tion to air bag module while allowing turning of steering wheel Activated(closed) when crash impact de- Crash sensor Diagnostic module to infktor Activated(closed) when crash impact de- S-sensor 1 Monitors com~onents and harnesses in tected Acting with D-sensor, completes circuit to inflator Remark Located in instrument cluster Location: Driver side . . . . . . . . in steering wheel hub Passenger side . . . above the glove compartment Part of combination switch Located in front part of vehicle(left, right, and center) Located behind heater unit in passenger compartment Contains back-up battery air bag system Indicates system malfunction by flashing or illuminating air bag system warning light If warning light is bunt, sounds warning buzzer Detects short circuit between air bag module and ground or crash sensor rnal- function and melts system fuse to pre- vent unintended air bag deployment Gartner Banana

Before beginning any service procedure. refer to section T of this manual for I air bag system service warnings and audio antitheft system alarm conditions . HEATER AND AIR CONDITIONER SYSTEMS ....................................... INDEX U- 2 ................................... HEATER U- 2 AIR CONDITIONER ......................... U- 3 TROUBLESHOOTING ......................... U- 4 CIRCUIT DIAGRAM ......................... U- 4 TROUBLESHOOTING GUIDE ................ U- 5 ..................................... HEATER U-15 ........................ STRUCTURAL VIEW U-15 HEATER UNIT .............................. U-16 BLOWER UNIT ............................. U-18 HEATER CONTROL UNIT .................... U-20 AIR CONDITIONER ........................... U-23 PREPARATION ............................. U-23 STRUCTURAL Vl EW ........................ U-23 SERVICE WARNINGS ....................... U-24 SERVICE CAUTIONS ........................ U-24 REFRIGERANT SYSTEM SERVICE PROCEDURE .............................. U-25 COOLING UNIT ............................. U-30 CONDENSER AND RECEIVER DRIER ........ U-33 REFRIGERANT LINES ....................... U-35 CONDENSER FAN .......................... U-36 AIC RELAY ................................. U-37 ................... CONDENSER FAN RELAY U-37 REFRIGERANT PRESSURE SWITCH ......... U-37 NC COMPRESSOR ......................... U-38 45U0Ux-001 Gartner Banana