Saab 9000 - Page 61

58 Technical Description
A/C compressor
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59
<500
When the A/C compressor is activated, either from
the ACC control module or by means of the A/C but-
ton on the dashboard, positive battery voltage (B+)
is applied to pin 59 of the Trionic control module via
the EDU, antifrost thermostat and pressure switch.
The control module then opens the idle air control
valve slightly wider to prepare for the forthcoming
load increase. After a short delay the control module
grounds pin 54, which is connected to the A/C relay.
The ECM breaks the circuit to pin 54 if the engine has
not yet been started.
Saab 9000
.__
___ 54
589
µp
µp