Air Conditioning Clutch Switch
WARNING: This page does not describe the selected car, but rather 13 other vehicles, including the 2003 Mazda B4000, 2003 Mazda B3000, 2003 Mazda B2300, 2002 Mazda B4000, and 2002 Mazda B3000. However, it is still accessible from the selected car via links, so may be relevant.
On factory installed A/C system, PCM receives signal voltage from Air Conditioning Clutch (ACC) switch indicating that the air conditioning compressor clutch is engaged. PCM uses the ACC switch signal to adjust line pressure to compensate for additional engine load. If ACC switch fails with closed contacts, line pressure will be slightly lower with air conditioning off. If ACC switch fails with open contacts, line pressure will be slightly higher with air conditioning on.