Oem System Circuits: Other Scion tC I рестайлинг

Relay Blocks

Ground Points

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System Outline

The engine control system utilizes a microcomputer and maintains overall control of the engine, transaxle etc. An outline of the system is given here.

1. Input Signals Engine coolant temp. signal circuit The engine coolant temp. sensor detects the engine coolant temperature and has a built-in thermistor that's resistance varies according to the engine coolant temperature. The engine coolant temperature is then sent to TERMINAL THW of the engine control module as a control signal. Intake air temp. signal circuit The intake air temp. sensor is installed in the mass air flow meter and detects the intake air temperature which is input as a control signal to TERMINAL THA of the engine control module. Oxygen density signal circuit The oxygen density in the exhaust emissions is detected by the heated oxygen sensor and sent as a control signal to TERMINAL OX1B of the engine control module. RPM signal circuit The camshaft and crankshaft positions are detected by the camshaft position sensor and crankshaft position sensor. The camshaft position is sent as a control signal to TERMINAL G2+ of the engine control module, and engine RPM is sent into TERMINAL NE+. Throttle position signal circuit The throttle body assembly detects the throttle valve opening angle and sends it as a control signal to TERMINALS VTA1 and VTA2 of the engine control module. Vehicle speed circuit The speed sensors detect the vehicle speed and send it to the skid control ECU with actuator, which sends it to TERMINAL SPD of the engine control module via the combination meter. Battery signal circuit Voltage is constantly applied to TERMINAL BATT of the engine control module. When the ignition SW is turned on, the voltage for the engine control module start-up power supply is applied to TERMINALS +B and +B2 of the engine control module via the EFI relay. Stop lamp SW signal circuit The stop lamp SW is used to detect whether the vehicle is braking or not and the signal is sent to TERMINAL STP of the engine control module as a control signal. Starter signal circuit To confirm whether the engine is cranking, the voltage that is being applied to the starter motor during cranking is detected and the signal is sent to TERMINAL STA of the engine control module as a control signal. Engine knock signal circuit Engine knocking is detected by the knock control sensor and the signal is sent to TERMINAL KNK1 as a control signal. Air fuel ratio signal system The air fuel ratio is detected and sent as a control signal to TERMINAL A1A+ of the engine control module.
2. Control System * SFI system The SFI system monitors the engine condition through the signals received from each sensor by the engine control module. And a control signal is output from TERMINALS #1, #2, #3 and #4 of the engine control module to operate the fuel injector (Inject the fuel). The SFI system uses the engine control module to control the fuel injection operation in response to the driving conditions. * ESA system The ESA system monitors the engine conditions through the signals received by the engine control module from each sensor. The best ignition timing is decided according to this data. Then the data stored in the engine control module and the control signals are output from TERMINALS IGT1, IGT2, IGT3, IGT4. These signals control the ignition coils (Igniter) to provide the best ignition timing for the driving conditions. * Heated oxygen sensor heater control system The heated oxygen sensor heater control system turns the heater on when the intake air volume is low (Temp. of exhaust emissions is low), and warms up the heated oxygen sensor to improve detection performance of the sensor. The engine control module evaluates the signals from each sensor, and outputs current to TERMINAL HT1B to control the heater.
3. Diagnosis System Via the diagnosis system, when there is a malfunction in the engine control module signal system, the malfunctioning system is recorded in the memory. The malfunctioning system can be found by reading the code displayed by the check engine warning lamp.
4. Fail-Safe System When a malfunction has occurred in any system, if there is a possibility of engine trouble being caused by continued control based on the signals from that system, the fail-safe system either controls the system by using data (Standard values) recorded in the engine control module memory or else stops the engine.

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Multiplex communication system (CAN) uses a serial communication protocol and communicates with a differential voltage. In this network system, TERMINALS CANH and CANL are used for communication between the ECUs and sensors, and it provides an excellent data communication speed and communication error detecting facilities.

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The interior light is controlled by the integration relay. This system has following features.

Illuminated Entry System

* When a door is unlocked through a key operation or transmitter operation, or if a door is opened or closed, the illuminated entry system turns ON the room lamp (Center), map lamp and the ignition key cylinder lamp.

* If the ignition switch is turned to the ACC or ON position or if all doors are locked during the 15 seconds in which these lights are ON, they will immediately turn OFF.

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When the ignition SW is turned on, current flows to TERMINAL 17 of the wiper and washer SW and TERMINAL 2 of the windshield wiper motor through the FR WIP fuse. The current flows to TERMINAL 1 of the windshield washer motor through the FR WSH fuse.

1. Low Speed Position When the wiper and washer SW is turned to the LO position, current flows in TERMINAL 17 of the wiper and washer SW, out TERMINAL 7 to TERMINAL 1 of the windshield wiper motor, and finally out TERMINAL 5 to GROUND and causes the windshield wiper motor to run at low speed.
2. High Speed Position When the wiper and washer SW is turned to the HI position, the current flows in TERMINAL 17 of the wiper and washer SW, out TERMINAL 8 to TERMINAL 4 of the windshield wiper motor, and finally out TERMINAL 5 to GROUND and causes the windshield wiper motor to run at high speed.
3. INT Position When the wiper and washer SW is turned to the INT position, the wiper relay activates and current flows in TERMINAL 17 of the wiper and washer SW then out TERMINAL 2 to GROUND. This activates the intermittent circuit and the current which flows in TERMINAL 17 of the wiper and washer SW then out TERMINAL 7 to TERMINAL 1 of the windshield wiper motor and finally out TERMINAL 5 to GROUND activating the wipers. The intermittent operation is controlled by the charging and discharging of a condenser installed in the relay.
4. Washer Continuous Operation When the wiper and washer SW is pulled to the WASHER position (Washer SW ON position), the current flows from the FR WSH fuse to TERMINAL 1 of the windshield washer motor then out TERMINAL 2 and into TERMINAL 11 of the wiper and washer SW. It then flows out TERMINAL 2 to GROUND and causes the windshield washer motor to run and the window washer to spray water onto the windshield. Simultaneously, current flows from the FR WIP fuse to TERMINAL 17 of the wiper and washer SW, out TERMINAL 7 to TERMINAL 1 of the windshield wiper motor and then out TERMINAL 5 to GROUND, causing the wipers to function.

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1. Manual Up and Down Function This function opens or closes the window as long as the power window switch is being pulled up or pushed down (Should be pulled up or pushed down only a single step for manual operation.). The window stops as soon as the switch is released.
2. One-Touch Auto Up and Down Function "One-touch auto up and down function" enables the windows on the front doors to be fully opened or closed with a single touch of the power window switch.
3. Jam Protection Function The jam protection function automatically stops the power window and moves it downward if a foreign object gets jammed in the path of the window during one-touch auto-up operation.
4. Remote Control Function The up and down operation of the front passenger door windows can be controlled by operating the power window master switch.
5. Key-Off Operation Function For about 43 seconds after turning OFF the ignition SW or until the driver's or passenger's door is opened, this function enables the door windows to be operated via the power window master switch and/or the manual operation available on each passenger's seat door. * If the battery terminal or fuse is disconnected, the glass position of all door windows have to be reset to their initial positions, one by one, by using the power window control switch and by following the procedure below: Reconnect the battery terminal or fuse. Turn ON the ignition switch. Lower the window of each door halfway or more with the power window switch. Then close the window fully with the power window switch. Do not release the switch for at least 2 seconds after the window has fully closed.

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1. Manual Down or Up Operation When the power window master SW is pushed down one stop, the motor rotates to open the window. When the power window master SW is pulled up one step, the motor rotates in the opposite direction, to close the window. All the other windows can be opened or closed as well, by the operating the power window master SW or respective power window SW. When the window lock SW is pushed to the lock side, the ground circuit to the passenger windows opens. As a result, even if an Open or Close operation is attempted on any of the passenger windows, the current from TERMINAL E of the power window master SW is not grounded and the motor does not rotate. So the passenger's window can not be operated and the window lock occurs.
2. Auto Down Operation (Driver's Window) When the power window master SW is pushed down two steps, the motor rotates to open the window automatically.
3. Stopping of Auto Down Operation (Driver's Window) Auto operation can be stopped mid course with pulling the power window master SW up one step during the down operation.

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The door lock control is a system controlled by various signals sent to the integration relay.

1. Manual Unlock Operation When the door lock control SW of the driver's or passenger's side door is pushed to UNLOCK, the door unlocks.
2. Manual Lock Operation When the door lock control SW of the driver's or passenger's side door is pushed to LOCK, the door locks.
3. Door Key Unlock Operation * Unlock operation from driver's side door When the driver's side door is unlocked once using a mechanical key, only the driver's side door unlocks. If this operation is repeated within 3 seconds, all the other doors also unlock.
4. Ignition Key Reminder Operation If the ignition key is still inserted in the ignition key cylinder and the driver door is open, any locking operations using the lock knob on the driver's door will not take effect but will instead automatically unlock the door. When the door is locked with the manual door lock SW on the driver door or door key SW in the driver door, the door locks once but immediately after that, the door will unlock again automatically.

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Door lock control (Lock and unlock) and panic control (Theft alarm and flash) is performed by remote control, without the ignition key needing to be inserted in the door key cylinder, using low-power electrical waves emitted by a transmitter.

1. Normal Operation * Lock operation When the lock SW on the transmitter is pressed, all the doors are locked. * Unlock operation When the unlock SW on the transmitter is pressed once, only the driver door is unlocked. When the unlock SW is pressed again within 3 seconds, all the doors are unlocked.
2. Auto Lock Function If the door is not actually opened within 30 seconds after the door has been unlocked by the unlock SW on the transmitter, all the doors are automatically re-locked. If any of the following conditions are detected, the wireless door lock does not function. * Any door is opened. * The ignition key is inserted into the ignition SW. * When the lock detection SW of the door is locked.
3. Wireless Door Lock Stop Function If any of the following conditions are detected, the wireless door lock does not function. Lock operation * When any door is open (Door courtesy SW on) * The ignition key is inserted into the ignition SW (Unlock warning SW on) * Ignition SW is on Unlock operation * Ignition SW is on
4. Visual Confirmation of Lock or Unlock During lock operation, when the integration relay receives a lock signal from the door lock detection SW, the turn signal lamps are flashed once. During unlock operation, when the integration relay receives an unlock signal from the door lock detection SW, the turn signal lamps are flashed twice.
5. Remote Panic Operation The panic operation will function regardless of whether the doors are locked or unlocked, open or closed. When the panic button (Transmitter) is pushed once, the map lamp, room lamp (Center) and ignition key cylinder lamp light up, and the theft alarm and horn sound and the turn signal lamps, headlamps and tail lamps flash. Then, if the panic, lock or unlock buttons (Transmitter) are pushed once more, the map lamp, room lamp (Center) and ignition key cylinder lamp will be turned off, the horn, alarm and light sounding and flashing will stop. The panic operation will not function if the ignition key is in the ignition key cylinder.
6. Repeat Function If the lock detection signal, in response to the output signal, is not received after the integration relay has output the lock signal, the lock signal is output again.

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If the vehicle is stationary (Speed is less than 5 km/h), the back door opener motor activates under the control of the integration relay when the back door opener SW is pushed. It results in releasing the latch on the back door to open back door.

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Current is always applied from the S/ROOF fuse to TERMINAL 5 of the sliding roof control ECU. When the ignition SW is turned on, current from the ECU-IG fuse flows to TERMINAL 8 of the sliding roof control ECU.

1. Sliding Roof Open/Close Operation To operate the sliding roof, use the two sliding roof control switches: "Slide open/tilt up"; and "Slide close/tilt down." When a switch is pressed and held down for several seconds, the one touch automatic operation activates in accordance with the function of the switch.
2. Key-Off Operation The roof can continue to be operated - for about 43 seconds after the ignition SW has been turned from ON to OFF or until the driver's or passenger's door is opened, whichever occurs first. However, if an overload reverse operation is active at that time, the operation will continue until it comes to an end.
3. Overload Reverse Operation The sliding roof control ECU detects jams in the sliding roof operation, if they occur, from abnormal motor speed signals and reverses the sliding roof operation. * When the battery terminal or fuse is disconnected, the roof position has to be reset to its initial position by the sliding roof control SW by following the procedure below: Reconnect the battery terminal or fuse. Turn ON the ignition switch. Operate the sliding roof control SW to open the roof halfway or more. Then operate the sliding roof control SW to fully close the roof. Do not release the switch for at least 2 seconds after the roof is fully closed.

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When the ignition SW is turned to the ACC position, current from the ACC fuse flows to TERMINAL 6 of the shift lock control ECU. When the ignition SW is turned to ON position, current from the ECU-IG fuse flows to TERMINAL 1 of the shift lock control ECU.

1. Shift Lock Mechanism If the brake pedal is depressed while the ignition SW is in the ON position (The stop light SW is on), the shift lock control ECU is activated, allowing the driver to change the shift lever to a position other than the P position.
2. Key Interlock Mechanism If the ignition SW is in the ON or ACC position, and the shift lever is put into the P position, the current flowing from TERMINAL 12 of the shift lock control ECU to key interlock solenoid is cut off. This causes the key interlock solenoid to turn off (Lock lever disengages from LOCK position) and the ignition key can be turned from the ACC to LOCK position.

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Previous automatic transaxles have selected each gear shift using mechanically controlled throttle hydraulic pressure, governor hydraulic pressure and lock-up hydraulic pressure. An electronically controlled transmission, however, electrically controls the line pressure and lock-up pressure etc., through solenoid valves. The engine control module adjusts each solenoid valve based on the signals received from each sensor, and makes smooth driving possible by selecting the gear that is most appropriate to the driving conditions at that time.

1. Gear Shift Operation When driving, the engine warm up condition is sent as a signal to TERMINAL THW of the engine control module from the engine coolant temp. sensor, and the vehicle speed signal is sent to TERMINAL SPD of the engine control module. At the same time, the throttle valve opening signal from the throttle body assembly is sent to TERMINALS VTA1 and VTA2 of the engine control module as a throttle angle signal. Based on these signals, the engine control module selects the best shift position for the driving conditions and sends current to the electronically controlled transmission solenoid.
2. Lock-Up Operation When the engine control module determines that lock-up operation conditions have been met, current flows from TERMINAL S4 of the engine control module to TERMINAL 8 of the electronically controlled transmission solenoid to GROUND, giving power to the lock-up solenoid and initiating a lock-up operation.
3. Clutch Pressure Control The electronically controlled transmission solenoid is controlled by current from TERMINAL SLT+ of the engine control module, and controls the accumulator hydraulic pressure. As a result, the clutch to hydraulic pressure is adjusted precisely, and allows for stable shift changes.
4. Line Pressure Control The engine control module optimizes the line hydraulic pressure by controlling TERMINAL SLT+ of the module according to the engine torque data. This further enables smooth gear shifting.
5. Shifting Control in Uphill/Downhill Traveling This system determines whether the vehicle is traveling on an incline or decline from the throttle opening angle, vehicle acceleration condition and brake pedal operation, and controls the shift up to O/D to allow smooth driving.
6. Clutch to Clutch Control When shifting from the 1st gear to the 2nd gear and the 2nd gear to the 3rd gear, signals from the engine control module TERMINALS SL1+ and SL2+ control the electronically controlled transmission solenoid, to control the drain orifice hydraulic pressure (Switch orifice). The electronically controlled transmission solenoid is also controlled by the current from the engine control module TERMINALS SL1+ and SL2+, to adjust the hydraulic pressure precisely, which ensures smooth shifting.
7. Stop Lamp SW Circuit If the brake pedal is depressed (Stop lamp SW on) when driving in lock-up condition, a signal is input to TERMINAL STP of the engine control module, the engine control module operates and continuity to the lock-up solenoid is cut.

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The cruise control system is a constant vehicle speed controller which makes it possible to automatically adjust the opening of the engine throttle valve via a switch on the steering wheel, without depressing the accelerator pedal.

1. Set Operation When the ON-OFF SW is turned on, the system starts preparations necessary for the cruise control and turns on the indicator light in the combination meter.
2. Set Speed Control When the - SET SW is operated while the ON-OFF SW is turned on when driving, the vehicle will be maintained at the current speed.
3. Coast Control When the - SET SW is held down on during cruise control driving, the engine control module adjusts the throttle valve to gradually decelerate the vehicle. Every time the - SET SW is tapped momentarily, the vehicle speed is decelerated by approximately 1.6 km/h. However, in the case of a tap-down operation which puts a difference of more than 5 km/h between the set speed and the actual vehicle speed, the device records the speed when the switch was released and maintains it at that speed constantly.
4. Accel Control When the + SET SW is held down during cruise control driving, the engine control module adjusts the throttle valve to gradually accelerate the vehicle. Every time the + SET SW is tapped momentarily, the vehicle speed is accelerated by approximately 1.6 km/h. However, in the case of tap-up operation which puts a difference of more than a 5 km/h between the set speed and the actual vehicle speed, the device does not change the set speed. (Tap-up operation is not available.)
5. Resume Control If the vehicle speed falls below the low speed limit and the cruise control is cancelled, the preset speed will still be retained in memory. However, the resume control will only be available when the vehicle speed is above the low speed limit.
6. Manual Cancel Mechanism If any of the following signals are input during cruise control driving, the cruise control will be cancelled. * The stop lamp SW is turned on. (The brake pedal is depressed) * The CANCEL SW is turned on. * The ON-OFF SW is turned off. * The cruise control clutch SW is turned off. (M/T) (The clutch pedal is depressed) * Gear is shifted from position D or 3 to other positions. (A/T)
7. Auto Cancel Function If any of the following conditions are encountered, the cruise control will be automatically cancelled. * Disconnection and/or short in the stop light SW * Malfunction in the vehicle speed signal * Malfunction in the electronic throttle parts * Malfunction in the stop lamp SW input circuit * Malfunction in the cancel circuit * The actual vehicle speed falls below the minimum speed limit * The actual vehicle speed falls to 16 km/h or more below the set speed
8. Overdrive Control Function The overdrive will sometimes be cut off on hills during cruise control driving. When the hill climbing hills stops, as determined by the throttle opening degree information, control will be reset to the overdrive condition after the overdrive timer has reset. Also, when the overdrive is cut off during accelerator control or resuming control, control is returned to the overdrive condition when the accelerator control and resuming control have finished.

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* ABS system

This system controls the brake fluid pressure acting on the disc brake cylinders of the right front wheel, left front wheel and rear wheels when the brakes are applied in an emergency stop so that the wheels do not lock. This results in improved directional stability and steerability during emergency braking.

1. Input Signals Speed sensor signal The speed of each of the wheels is detected and sent to TERMINALS 9, 11, 31 and 33 of the skid control ECU with actuator. Stop light SW signal A signal is sent to TERMINAL 10 of the skid control ECU with actuator when the brake pedal is depressed.
2. System Operation During sudden braking, the skid control ECU with actuator receives signals from each sensor, which it uses to send a current to the solenoid inside the actuator allowing the hydraulic pressure acting on the wheel cylinders to escape to the reservoir. The pump inside the actuator also operates at this time returning brake fluid from the reservoir to the master cylinder, thus preventing the vehicle wheels from locking. If the skid control ECU with actuator determines that the hydraulic pressure acting on the wheel cylinders is insufficient, the current to the solenoid is adjusted and the hydraulic pressure is increased. The skid control ECU with actuator can also maintain the hydraulic pressure at a constant level, using the same method as above. The pressure is repeatedly reduced, increased, or maintained to ensure vehicle stability and improve steerability during sudden braking.

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The tire pressure warning valve and transmitter installed in the tire wheel detects the tire air pressure and transmits signals to the vehicle side receiver. When the detected tire air pressure is below a specified level, the warning light in the combination meter comes on to inform the driver.

Press the tire pressure warning reset SW for 3 seconds with the ignition SW in the ON position after the tire pressure is adjusted to the specified value. It will set the tire pressure warning ECU to issue the low pressure warning when the pressure drops below the specified level.

Warnings when the tire pressure is low

* When the tire air pressure is below the specified level, the warning light in the combination meter comes on.

SRS

Note. When inspecting or repairing the SRS, perform service in accordance with the following precautionary instructions and the procedure, and precautions in the service information applicable for the model year.

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1. Malfunction symptoms of the SRS are difficult to confirm, so the DTCs become the most important source of information when troubleshooting. When troubleshooting the SRS, always inspect the DTCs before disconnecting the battery.
2. Work must be started more than 90 seconds after the ignition SW is turned to the "LOCK" position and the negative (-) terminal cable is disconnected from the battery. (The SRS is equipped with a back-up power source so that if work is started within 90 seconds from disconnecting the negative (-) terminal cable of the battery, the SRS may deploy.)
3. When the negative (-) terminal cable is disconnected from the battery, the memory of the clock and audio system will be cleared. So before starting work, make a record of the contents in the audio memory system. When work is finished, reset the audio systems as they were before and adjust the clock. Some vehicles have power tilt steering, power telescopic steering, power seat and power outside rear view mirror which are all equipped with memory function. However, it is not possible to make a record of these memory contents. So when the work is finished, it will be necessary to explain it to your customer, and ask the customer to adjust the features and reset the memory. To avoid erasing the memory in each system, never use a back-up power supply from outside the vehicle.
4. Before repair, remove the airbag sensor if shocks are likely to be applied to the sensor during repair.
5. Do not expose the following parts directly to hot air or flame
6. Even in cases of a minor collision where the SRS does not deploy, the following parts should be inspected
7. Never use SRS parts from another vehicle. When replacing parts, replace with new parts.
8. For the purpose of reuse, never disassemble and repair the following parts.
9. If the following parts have been dropped, or have cracks, dents and other defects in their case, bracket, and connector, replace with new one.
10. Use a volt/ohmmeter with high impedance (10 kohms/V minimum) for troubleshooting electrical circuits of the system.
11. Information labels are attached to the periphery of the SRS components. Follow the instructions of the notice.
12. After work on the SRS is completed, check the SRS warning light.
13. If the vehicle is equipped with a mobile communication system, refer to INTRODUCTION .

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* The system reaches an ignition judgment to deploy the following device based on the signals received from the front airbag sensor and deceleration sensor.

1. Driver Airbag
2. Front Passenger Airbag
3. Knee Airbag
4. Seat Belt Pretensioner

* The system reaches an ignition judgment to deploy the following device based on the signals received from the side airbag sensors.

1. Side Airbags
2. Curtain Shield Airbags

* The dual-stage SRS airbag system has been used for the driver and front passenger airbags. This system controls the optimal airbag inflation by judging the extent of impact, seat position (driver seat) and whether or not the seat belt is fastened (driver seat) and information from the Front Passenger Occupant Classification System.

* The front passenger occupant classification system judges whether the front passenger seat is occupied by an adult or child (with child seat) or is unoccupied, according to the load applied to the front passenger seat and whether the seat belt is buckled. Based on the results, it restricts the deployment of the front passenger airbag, front passenger side airbag, and front passenger seat belt pretensioner. In addition, the system informs the driver of the result of the judgment through the use of the AIRBAG ON/OFF indicator lights.

* The airbag sensor assembly transmits a signal to the Engine Control Module in order to stop the fuel pump.

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Current is always applied from the ECU-B fuse to TERMINAL 3 of the combination meter. When the ignition SW is turned to ON position, the current from the MET IG2 fuse flows to TERMINAL 4 of the combination meter.

Key Reminder System

When the driver door is opened when the ignition SW off but the ignition key is still in the key cylinder (Unlock warning SW on), a signal is input from the unlock warning SW to TERMINAL 7 of the combination meter, and from the door courtesy SW (Driver's side) to TERMINAL 8 of the combination meter. As a result, the buzzer in the combination meter sounds, warning the driver that the key is still in the key cylinder.

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The current is applied at all times to TERMINAL 3 of the combination meter through the ECU-B fuse.

When the ignition SW is turned to ON position, current flows to TERMINAL 4 of the combination meter through the MET IG2 fuse. When the light control SW is turned to the Tail or Head position, current is applied to TERMINAL 6 of the combination meter through the PANEL fuse.

Light Reminder System

When the light control SW is in the Tail or Head position, the ignition SW turned to OFF from ON position, the ignition key is not in the key cylinder and the driver door is opened (Door courtesy SW on), current flows to TERMINAL 4 of the combination meter stops. As a result, the combination meter is activated and current flows from TERMINAL 3 of the combination meter, the buzzer in the combination meter sounds to remind the driver that the lights are still on.

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Current is always applied from the ECU-B fuse to TERMINAL 3 of the combination meter. When the ignition SW is turned to the ON position, the current from the MET IG2 fuse flows to TERMINAL 4 of the combination meter.

Seat Belt Warning System

When the ignition SW is turned on, a signal is sent to the combination meter. To determine whether the driver has fastened the seat belt, a signal is sent from the front seat inner belt (Driver's side) to TERMINAL 5 of the combination meter. If the seat belt is not fastened, the seat belt warning light in the combination meter blinks, and emits a warning sound.

In addition, if a front passenger is detected by the sensor (Occupant detection sensor) which is installed in the front passenger seat, it is then determined whether the passenger's seat belt is fastened or not. If not fastened, the signals from the front seat inner belt (Front passenger's side) are sent to TERMINAL 22 of the combination meter, and the passenger's seat belt warning lamp blinks.

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Fan Motor Operation

When the ignition SW is turned on, current flows through the ECU-IG fuse to the FAN NO. 1 relay (Coil side), FAN NO. 2 relay (Coil side) and FAN NO. 3 relay (Coil side).

1. Low Speed Operation When only the A/C system is activated, the A/C condenser fan motor and the radiator fan motor rotate at low speed. When the A/C system is activated, current from the ECU-IG fuse flows to the FAN NO. 3 relay (Coil side) to TERMINAL 2 of the diode (Fan), out TERMINAL 3 to TERMINAL (B) 2 of the engine control module causing the FAN NO. 3 relay to turn on. As a result, the current flows through the CDS fuse to TERMINAL 5 of the FAN NO. 3 relay, out TERMINAL 3 to TERMINAL 2 of the A/C condenser fan motor, then out TERMINAL 1 to TERMINAL 3 of the FAN NO. 2 relay, and out TERMINAL 4 to TERMINAL 2 of the radiator fan motor then finally out TERMINAL 1 to GROUND. As the motors are in series, they only rotate at low speed.
2. High Speed Operation When the pressure SW is turned on and/or the engine control module activated, the A/C condenser fan motor and the radiator fan motor rotate at high speed. When the pressure SW is turned on, current flows through the ECU-IG fuse to the FAN NO. 1 and NO. 2 relay (Coil side), out TERMINAL 3 of the pressure SW, the out TERMINAL 2 to GROUND, and the current which flows through the ECU-IG fuse goes to the FAN NO. 3 relay (Coil side), then to TERMINAL 2 of the diode (Fan), and out TERMINAL 1 to TERMINAL 3 of the pressure SW, then from TERMINAL 2 to GROUND. As a result, the FAN NO. 1, NO. 2. and NO. 3 relays are turned on. At the same time, current from the RDI fuse flows to the FAN NO. 1 relay (Point side), then to TERMINAL 2 of the radiator fan motor, and out TERMINAL 1 to GROUND, and current from the CDS fuse flows to the FAN NO. 3 relay (Point side) to TERMINAL 2 of the A/C condenser fan motor, then out TERMINAL 1 to TERMINAL 3 of the FAN NO. 2 relay, and out to TERMINAL 5 to GROUND. As the current is flowing in parallel to the motors, they rotate at high speed. When the engine control module is activated, the current from the ECU-IG fuse flows to the FAN NO. 1 and NO. 2 relays (Coil side), then to TERMINAL (E) 14 of the engine control module, and the current from the ECU-IG fuse flows to the FAN NO. 3 relay (Coil side) to TERMINAL 2 of the diode (Fan), and out TERMINAL 1 to TERMINAL (E) 14 of the engine control module. As a result, the FAN NO. 1, NO. 2 and NO. 3 relays are turned on. At the same time, current from the RDI fuse flows to FAN NO. 1 relay (Point side) to TERMINAL 2 of the radiator fan motor, and out TERMINAL 1 to GROUND, and current from the CDS fuse flows to the FAN NO. 3 relay (Point side) to TERMINAL 2 of the A/C condenser fan motor, out TERMINAL 1 to TERMINAL 3 of the FAN NO. 2 relay, then out TERMINAL 5 to GROUND. As the current is flowing to the motors in parallel, they rotate at high speed.

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1. Heater Blower Operation When the blower speed is set to a certain level using the blower control SW, the A/C control assembly sends signals to the blower control to control the blower motor speed.
2. Damper Servo Motor (Air Inlet) Control When the FRESH/RECIRC select SW is set to RECIRC, the motor in the damper servo motor (Air inlet) starts rotating and moves the damper toward the RECIRC side. Since the damper position is detected by TERMINAL REC of the A/C control assembly, the motor continues to rotate until the damper reaches its stop position. When the FRESH/RECIRC select SW is set to FRESH, the motor in the air inlet control servo motor starts rotating to move the damper toward the FRESH side. Since the damper position is detected by TERMINAL FRS of the A/C control assembly, the motor continues to rotate until the damper reaches its stop position.
3. Damper Servo Motor (Air Vent Mode) Control When the mode select SW is pushed, the ECU in the A/C control assembly activates the damper servo motor (Air vent mode). This causes the servo motor to rotate to the position (FACE, BI-LEVEL, FOOT, FOOT/DEF, DEF) selected using the mode select SW, and moves the damper.
4. Damper Servo Motor (Air Mix) Control When the temperature control SW is pressed, the ECU in the A/C control assembly sends a signal to the damper servo motor (Air mix). This signal drives the motor to reach the temperature set by the temperature control SW, and moves the damper.
5. Air Conditioning Operation The A/C control assembly receives various signals, I.E., the engine RPM from the engine control module, out side air temperature signal from the ambient temp. sensor and coolant temperature from the engine control module, etc. When the engine is started and the A/C SW (A/C control assembly) is on, a signal is sent to the engine control module. As a result, the ground circuit in the engine control module is closed and current flows from the ECU-IG fuse to TERMINAL 1 of the MG/C relay then out TERMINAL 2 to TERMINAL MGC of the engine control module, turning the MG/C relay on, so that the magnetic clutch turns on. At the same time, the A/C control assembly detects that the magnetic clutch is on and the A/C compressor operates. If the A/C control assembly detects any of the following conditions, it stops the air conditioner: * Evaporator outlet air is too low. * There is a marked difference between the compressor speed and the engine speed. * The refrigerant pressure is abnormally high or abnormally low. * The engine speed is too low. * Rapid acceleration occurs.
6. DEF Synchronized Control Function When the blower SW is on and the air vent mode control SW is turned to the DEF or FOOT DEF position, if causes the A/C to run, regardless of whether A/C SW is on or not.