Technician Handbook Air Conditioning for Collision Repair Basic AC System Checks A basic check of the mechanical operation and performance of the AC system will often reveal problems. You can perform simple and easy-to-do “ sight, sound and temperature ” checks of the AC system. AC Indicator Light Is the AC indicator light blinking? • This indicates problems with the compressor or AC ECU. Follow related diagnostic procedures for the blinking indicator before moving on to any performance or pressure tests.
- A blinking AC light can indicate a compressor speed problem from a slipping, oily or damaged drive belt; slipping, damaged or incorrectly shimmed compressor clutch; overcharged system causing a slipping belt or compressor clutch; damaged, loose or intermittently shorted AC compressor wire. - The least likely causes include an actual compressor lock-up condition or a malfunctioning lock-up sensor on the compressor. AC Outlet Temperature Is the AC outlet temperature and air flow normal? • Check the center outlet using a thermometer. • Make sure a few windows are down or a door is open and the system is not set on MAX A/C.
• The outlet temperature should be between 35-45° F depending on ambient temperature and humidity. 24 Collision Repair & Refinish Training