Air conditioning (Japan) (page 2 of 2)

Aircon blower motor, switch and resistor pack One terminal of the aircon blower motor receives battery voltage from link 2 in the engine compartment fuse box via the starter switch, the auxiliary relay (provided it is energized) and fuse A7. When the blower switch is operated from the OFF position, an earth is switched on a UG wire to the other side of the aircon blower relay coil and simultaneously to the other terminal of the aircon blower motor via the resistor pack or direct dependent on the blower speed required. In addition, since battery voltage already exists on the aircon blower relay coil, the relay energizes, switching an earth via the relay contacts to the A/C thermostat.

Moving the blower switch from the OFF position increases the speed of the aircon blower motor incrementally as follows:

The first position provides a connection from earth via the blower switch and blower speed switch on a UG wire and via all three resistors in the pack to the aircon blower motor terminal on a UB wire. The second position provides a connection from earth via the blower switch and blower speed switch on a UY wire and via two resistors to the aircon blower motor terminal on a UB wire. The third position provides a connection from earth via the blower switch and blower speed switch on a UR wire and via one resistor to the aircon blower motor terminal on a UB wire. The fourth position provides an earth path on a UB wire direct to the aircon blower motor terminal.

Dual pressure switch The dual pressure switch consists of a high and a low pressure switch connected in series with the aircon request signal from the A/C thermostat to the MEMS ECM. In the event of pressure deviating from the normal condition, the relevant switch will open preventing the signal reaching the ECM and thereby inhibiting the system. When the correct pressure is restored the system will resume normal operation.