C-10, A/C Clutch Circuit Diagnosis

Turning on A/C system supplies battery voltage to A/C compressor clutch and Powertrain Control Module (PCM) terminal PB4 through Dark Green wire, increasing idle speed. PCM does not control A/C compressor clutch. If A/C compressor clutch is malfunctioning, repair basic A/C system problem. If A/C system is operating properly and idle speed drops too low when A/C compressor turns on or flares too high when A/C compressor turns off, check for an open in Dark Green wire to PCM. If Dark Green wire is okay, repair faulty PCM connection (terminal PB4) or replace faulty PCM.