A/C turns off while driving

THOMASL

MEMBER
1992 BUICK ROADMASTER
107,000 MILES

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?

1 Reply

HMAC300

MECHANIC
48,601 POSTS

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
IDENTIFICATION�.

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