SAAB WIS ONLINE

A/C relay

A/C relay



When the A/C compressor is activated from ACC, DICE will send bus information "A/C ON" provided all other conditions are fulfilled. The value is used by ECM.

The control module then calculates the impending torque requirement of the compressor using the A/C pressure and then requests a corresponding increase in mm 3 /combustion. After a short delay, the control module will ground pin 38, which is connected to the A/C relay.

The control module activates the relay only when the engine has been started.

Diagnostics


• If there is an open circuit or short circuit to ground, diagnostic trouble code P0646 will be generated.

• If there is a short circuit to B+, diagnostic trouble code P0647 will be generated.



System reaction to a fault

• AC relay disengages.


Note

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