When using the intelligent tester to troubleshoot the CAN communication line or LIN communication line:

Connect the intelligent tester to the vehicle, and turn a courtesy light switch on and off at 1.5 second intervals until communication between the intelligent tester and vehicle begins.

The back-up power source circuit for the air conditioning amplifier assembly is shown below. Power is supplied even when turning the engine switch off and is used for diagnostic trouble code memory, etc.

The main power source is supplied to the air conditioning amplifier assembly when the engine switch is on (IG). The power source is used for operating the air conditioning amplifier assembly and servo motor, etc.

The rear cooling unit expansion valve (rear magnetic valve) is controlled by the air conditioning amplifier assembly.

The rear blower motor (w/ rear heater) is operated by signals from the air conditioning amplifier assembly. The rear blower motor speed signals are transmitted by changes in the duty ratio.

Duty Ratio:

The duty ratio is the ratio of the rear blower motor OPEN time (T1) to the total of the rear blower motor OPEN and LO time (T2).

The rear blower motor controller controls the rear blower motor speed.

PTC heater relays are closed in accordance with signals from the air conditioning amplifier assembly and power is supplied to the quick heater assembly installed on the radiator heater unit.

When the No. 2 air conditioning control assembly (rear blower switch) is set to position LO or higher, the contact of the RR A/C relay is closed, current flows to the rear blower motor, and the rear blower motor operates. The rear blower motor speed can be changed by exchanging the ground and the rear blower resistor circuit with the No. 2 air conditioning control assembly (rear blower switch).

This circuit consists of the No. 2 air conditioning control assembly* and the air conditioning amplifier assembly. When the No. 2 air conditioning control assembly is operated, signals are transmitted to the air conditioning amplifier assembly through the LIN communication system.

If the LIN communication system malfunctions, the air conditioning amplifier assembly does not operate even if the No. 2 air conditioning control assembly is operated.

When the air conditioning amplifier assembly is turned on, a magnetic clutch on signal is sent from the MGC terminal of the air conditioning amplifier assembly. Then, the magnetic clutch relay turns on to operate the magnetic clutch.

The temperature control switch assembly LH and RH sends the temperature up and down signal to the air conditioning amplifier assembly through the multi-display assembly*1 or the air conditioning control assembly*2.