Air Conditioner Relay

When A/C switch is turned on with engine at idle, ISC servo is driven to increase engine speed. However, there is a delay before engine speed actually increases. During delay period, ECU opens relay circuit so compressor is not driven instantly. This prevents engine speed drop due to compressor load.

On automatic transaxle equipped models, during acceleration (throttle valve opening is 65 degrees or more) relay is cut off about 5 seconds to maintain good acceleration performance.