A/C High Side Switch - Installation
89chevy33Number: 90-78-1B
Section: 1B
Date: October 1989
Corporate Bulletin No.: 971206
Subject: SERVICE PROCEDURE "O" RING PUSH OUT DURING HIGH SIDE SWITCH INSTALLATION
Model and Year: 1988-90 J CAR WITH AIR CONDITIONING
TO: ALL CHEVROLET DEALERS
Due to a stack up of tolerances between the high side pressure switch or sensor and the high side port, some difficulty may be encountered when replacing a switch or sensor with the refrigerant system charged. The Schraeder valve may be depressed before the "O" ring is captured by the switch resulting in the "O" ring being pushed out of its sealing area causing a leak.
On vehicles with this condition, the "O" ring may be held in place by wrapping a string around the inboard side of the switch port while the switch is being screwed on (refer to Figure). This will hold the "O" ring in the switch port while the Schraeder valve is being depressed. Once the "O" ring is captured, the string should be removed and the switch screwed on until fully seated. The joint should then be leak checked with a refrigerant detector.
Redesigned parts will be in production during the 1990 model year.