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A/C Signal: Description and Operation

PURPOSE
Signals ECU when A/C is turned ON. ECU then activates the fast idle control device (FICD) solenoid valve to compensate for increased engine load by raising idle speed.

LOCATION
FICD is on firewall left of brake master cylinder.

OPERATION
When activated by the ECU, the FICD solenoid valve allows additional bypass air into the intake system, causing an increase in idle speed.