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A/C relay

A/C relay





When the A/C compressor is activated, either from the ACC control module or by the A/C button on the dashboard, DICE will send the information "A/C ON" out on the bus if the other conditions are fulfilled. The value is used by the Trionic T7.

The control module then calculates the impending torque requirement of the compressor on the basis of the A/C pressure and then requests a corresponding increase in the mass air flow/combustion. After a short delay the control module grounds pin 4, which is connected to the A/C relay.

The control module breaks the circuit to pin 4 before the motor has actually started.



Diagnostics


• In the event of a break or short-circuit to ground, diagnostic trouble code P1656 will be generated.

• In the event of a short-circuit to B+, trouble code P1657 will be generated.

Note

The A/C request from DICE can be read with the diagnostic tool.