A 1992 Buick Roadmaster with 5.7 liter V-8 A/C has full charge and cools perfectly while parked or idling. When driving the system will cut out and change from "auto" to "auto-econ" and no longer cool. When returned to idle the system can be restarted. While in park engine idle can be increased over 2000 rpm and system remains operable. What switch would cause this to occur?
Do this first, if it doesn't come up with a code then it will neeed to be scanned.
Entering Self Diagnostics
If a system fault is detected, the F/ C symbol will flash. To enter diagnostic mode, press and hold TEMP switch and press OFF switch. Temperature display shows stored fault codes. See FAULT CODE
Fault Code 09 can be cleared after servicing (adding refrigerant to) system by pressing OFF switch, while in self diagnostic mode.
FAULT CODE IDENTIFICATION
Fault Code Description
00 No System Faults
01 Temp. Air Valve Motor Circuit Open
02 Temp. Air Valve Motor Circuit Short
03 Outside Air Temperature Sensor Circuit Open
04 Outside Air Temperature Sensor Circuit Short
05 Inside Air Temperature Sensor Circuit Open
06 Inside Air Temperature Sensor Circuit Short
07 Sunload Sensor Circuit Open
08 Sunload Sensor Circuit Short
09 Low Freon
10 Universal Asynchronous Receiver Transmitter (UART) Failure