STEPPER MOTOR CRUISE CONTROL WILL NOT RESUME. Chevrolet Blazer

REVISION: 06/30/95

THIS BULLETIN IS BEING REVISED TO ADD F CAR INFORMATION. PLEASE DISCARD BULLETIN 56-90-02 (SECTION 9 - ACCESSORIES). ----------------------------------------------------------------------

SUBJECT: STEPPER MOTOR CRUISE CONTROL WILL NOT RESUME OR RESET (REPLACE SMCC MODULE)

MODELS: 1993-95 CHEVROLET CAMARO 1993-95 PONTIAC FIREBIRD WITH 3.4L V6 ENGINE (VIN S - RPO L32) AND AUTOMATIC TRANSMISSIONS (M30) ONLY OR WITH 5.7L V8 ENGINE (VIN P - RPO LT1) AND ANY TRANSMISSION

1994-95 CHEVROLET AND GMC TRUCK C/K, S/T, AND M/L MODELS

CONDITION:

SOME OWNERS MAY COMMENT THAT THE STEPPER MOTOR CRUISE CONTROL (SMCC) WILL INTERMITTENTLY CUT OUT AND WILL NOT RESUME OR RESET UNLESS THE IGNITION KEY IS CYCLED.

CAUSE:

THE SMCC IS SENSITIVE TO ANY BRAKE SWITCH CONTACT BOUNCE OF LESS THAN 32 MILLISECONDS. THIS CONTACT BOUNCE MAY CAUSE THE SMCC TO GO INTO A DIAGNOSTIC SHUT DOWN MODE UNTIL THE MODULE IS RESET BY TURNING THE IGNITION OFF. FOR TRUCKS, THE 1994 ZERO ADJUST BRAKE SWITCHES TEND TO AGGRAVATE THIS SENSITIVITY.

CORRECTION:

REPLACE THE SMCC MODULE ONLY IF THE DIAGNOSIS IN THE SERVICE MANUAL, SECTION 8A CRUISE CONTROL DOES NOT RESOLVE THE CONCERN.

SERVICE PROCEDURE

FOR 1994-95 CHEVROLET AND GMC TRUCK C/K, S/T, M/L MODELS: FOLLOW THE SMCC MODULE REMOVE AND INSTALL PROCEDURE USING THE APPROPRIATE SERVICE MANUAL.

FOR F-CAR MODELS, USE THE FOLLOWING PROCEDURE. REMOVE BEFORE REMOVING CRUISE CONTROL MODULE, DISCONNECT CRUISE CONTROL CABLE TO OBTAIN THE NECESSARY CLEARANCE.

1. DISCONNECT CRUISE CONTROL CABLE END FITTING FROM THROTTLE BODY LEVER STUD.

IF VEHICLE IS EQUIPPED WITH ACCELERATOR CONTROL/CRUISE CONTROL CABLE ADJUSTER (THROTTLE RELAXER), REMOVE CRUISE CONTROL CABLE END FITTING FROM ADJUSTER. NOTE LOCATION OF PULLEY FOR END FITTING.

2. UNLOCK CRUISE CONTROL CABLE CONDUIT BY PULLING UP ON UNLOCK BUTTON.

3. PUSH CONDUIT TOGETHER TO OBTAIN THE ADDITIONAL CABLE SLACK.

4. REMOVE CRUISE CONTROL MODULE PER SECTION 9B OF THE SERVICE MANUAL.

IMPORTANT: IT IS NOT NECESSARY TO REMOVE CRUISE CONTROL CABLE FROM VEHICLE.

INSTALL 1. INSTALL CRUISE CONTROL CABLE TO CRUISE CONTROL MODULE PER SECTION 9B OF THE SERVICE MANUAL.

IMPORTANT: CRUISE CONTROL MODULE RIBBON MUST NOT BE TWISTED WHEN INSTALLED TO CRUISE CONTROL MODULE.

2. INSTALL CRUISE CONTROL MODULE PER SECTION 9B OF THE SERVICE MANUAL.

3. CONNECT CRUISE CONTROL CABLE END FITTING TO THROTTLE BODY LEVER STUD.

IF VEHICLE IS EQUIPPED WITH ACCELERATOR CONTROL/CRUISE CONTROL CABLE ADJUSTER (THROTTLE RELAXER), CONNECT CRUISE CONTROL CABLE END FITTING TO ADJUSTER. NOTE CORRECT LOCATION OF PULLEY FOR END FITTING.

4. ADJUST CRUISE CABLE PER "CABLE ASSEMBLY ADJUSTMENT" PROCEDURE IN SECTION 9B OF THE SERVICE MANUAL.

IMPORTANT: EXCESSIVE CABLE SLACK IN CRUISE CONTROL CABLE WILL RESULT IN PERCEIVED SLOW MODULE RESPONSE.

PARTS INFORMATION

P/N NEW OLD DESCRIPTION QTY 25163349 25140906 1994 C/K MODULE 1 25163330 25111708 1995 C/K, M/L MODULE 1 25163349 25140906 1994-95 S/T MODULE 1 25140793 -- 1993-95 F MODULE 1

PARTS ARE CURRENTLY AVAILABLE FROM GMSPO.

WARRANTY INFORMATION

FOR VEHICLES REPAIRED UNDER WARRANTY, USE:

LABOR OP DESCRIPTION LABOR TIME R1220 MODULE, C/C REPLACE USE PUBLISHED LABOR OPERATION TIME

FIGURES: 0 ATTACHMENTS: 0

GENERAL MOTORS BULLETINS ARE INTENDED FOR USE BY PROFESSIONAL TECHNICIANS, NOT A "DO-IT-YOURSELFER". THEY ARE WRITTEN TO INFORM THOSE TECHNICIANS OF CONDITIONS THAT MAY OCCUR ON SOME VEHICLES, OR TO PROVIDE INFORMATION THAT COULD ASSIST IN THE PROPER SERVICE OF A VEHICLE. PROPERLY TRAINED TECHNICIANS HAVE THE EQUIPMENT, TOOLS, SAFETY INSTRUCTIONS AND KNOW-HOW TO DO A JOB PROPERLY AND SAFELY. IF A CONDITION IS DESCRIBED, DO NOT ASSUME THAT THE BULLETIN APPLIES TO YOUR VEHICLE, OR THAT YOUR VEHICLE WILL HAVE THAT CONDITION. SEE A GENERAL MOTORS DEALER SERVICING YOUR BRAND OF GENERAL MOTORS VEHICLE FOR INFORMATION ON WHETHER YOUR VEHICLE MAY BENEFIT FROM THE INFORMATION.