Cruise Control - Diagnostic Routine Modified

Number: 86-9
Section: 8A

Date: NOV., 1985
Subject: MODIFICATION OF DIAGNOSTIC ROUTINE ON THE CLARK BROS., KENT-MOORE, AND SPECMO CRUISE CONTROL "QUICK CHECKERS"
Model and Year: ALL CHEVROLET PASSENGER AND LIGHT DUTY TRUCKS WITH CRUISE CONTROL



TO: ALL CHEVROLET DEALERS


The existing diagnostic test procedure listed on the reverse side of these "Quick Checkers" includes five troubleshooting steps. Each step provides a reliable indication--by the illumination of a light--of the electrical continuity of specific components in the cruise control system. A large number of GM Dealership service personnel are under the misunderstanding that these same five steps, also, verify the condition of the cruise vacuum system. This is not the case. To clear up this mistaken assumption, an essential addition has been incorporated in the existing test procedure:
A sixth step (see chart) has been added. This step allows the technician to check the cruise system vacuum integrity from the accumulator tank through the vacuum servo.

To obtain the new diagnostic stickers, contact your zone office or divisional service contact representative. Place the sticker over the one presently on the "Quick Checker." If additional stickers are needed in the future, contact


SPECMO Enterprises 2344 N. Woodward Ave. Royal Oak, MI 48073 (313) 399-5645