WINDSHIELD WIPER SWITCH SERVICE PROCEDURES

PROCEDURES FOR SERVICING THE WIPER SYSTEM ON "S" SERIES LIGHT DUTY TRUCKS WERE OMITTED FROM THE 1982 "S" SERIES TRUCK SHOP MANUAL (ST-369 -82). USE THE FOLLOWING INFORMATION WHENEVER REPAIRS TO THE WIPER SYSTEM ARE NECESSARY. WINDSHIELD WIPER GENERAL DESCRIPTION THE WIPER SYSTEM IS A PERMANENT MAGNET POSITIVE PARK WIPER OFFERING SUPERIOR COOLING, A DYNAMIC BRAKE AND A SEPARATE WASHER PUMP ASSEMBLY. A UNIVERSAL WIPER SYSTEM TESTER (TOOL J-25079-C OR EQUIVALENT) IS AVAILABLE AND CAN BE USED TO GREATLY SIMPLIFY DIAGNOSING THE WIPER SYSTEM EITHER ON OR OFF THE CAR. A SEPARATE DIAGNOSTIC MANUAL IS DISTRIBUTED WITH THE TESTER. DIAGNOSIS THE DIAGNOSTIC PROCEDURES COVERED IN THIS ARTICLE ARE BASED ON CERTAIN TESTS AND OPERATIONAL CHECKS THAT WILL HELP LOCATE THE PROBLEM. PRIOR TO STARTING THE DIAGNOSIS PROCEDURE, IT IS VERY IMPORTANT TO CONFIRM THE REPORTED CONDITION WITH A COMPLETE OPERATIONAL CHECK INCLUDING THE WASHER SYSTEM. THEN MATCH UP THE CONDITION WITH ONE IN THE DIAGNOSIS CHARTS (1 THROUGH 9). WIPER ARM REMOVAL AND INSTALLATION 1.USE TOOL J-8966 OR EQUIVALENT AND LIFT ARM OFF TRANSMISSION SPINDLE SHAFT (FIG. 7). 2.TO INSTALL, REVERSE REMOVAL PROCEDURES AND CHECK OPERATION OF WIPERS. THE TOOL USED TO REMOVE THE WIPER ARMS CAN ALSO BE USED TO INSTALL THE ARMS. THE PROPER PARK POSITION IS SHOWN IN FIGURE 8. IF THE WIPER ARMS AND BLADES WERE IN CORRECT ADJUSTMENT PRIOR TO WIPER ARM REMOVAL, ADJUSTMENT SHOULD NOT BE REQUIRED. HOWEVER, IF ADJUSTMENT IS REQUIRED, IT CAN BE PERFORMED AS FOLLOWS. ADJUSTMENT REMOVE THE ARM(S) FROM THE SERRATED TRANSMISSION SPINDLE SHAFT, ROTATE THE ARM(S) THE REQUIRED DISTANCE AND DIRECTION THEN REINSTALL ON TRANSMISSION SPINDLE SHAFT IN POSITION AS SHOWN IN FIGURE 8. WIPER MOTOR MUST BE IN PARK POSITION. TRANSMISSION ASSEMBLY REMOVAL AND INSTALLATION (FIGURE 9) 1.DISCONNECT NEGATIVE BATTERY CABLE. 2.REMOVE WINDSHIELD WIPER ARMS. 3.REMOVE COWL VENT AND GRILLE. 4.REMOVE NUT SECURING LINKAGE TO MOTOR ASSEMBLY. 5.REMOVE SCREWS SECURING TRANSMISSIONS TO COWL PANEL. 6.INSTALL BY REVERSING REMOVAL PROCEDURE. TORQUE ATTACHING SCREWS AND NUTS TO 5.5-9 N.M (49-80 LB. IN.). WIPER MOTOR OPERATION INTERNAL PARTS OF THE WIPER MOTOR ASSEMBLY, FIELD MAGNET, ARMATURE, DRIVE GEAR, PARK SWITCH ACTUATOR AND BRUSH HOLDING ASSEMBLY ARE ENCLOSED IN AN ALUMINUM DIECAST HOUSING WITH A PLASTIC COVER. THE HOUSING AND COVER ARE ATTACHED TO EACH OTHER BY SEVEN RIVETS. THE WIPER IS EQUIPPED WITH A RADIO FREQUENCY INTERFERENCE SUPPRESSOR WHICH IS LOCATED IN THE TERMINAL CONNECTOR ON THE WIPER MOTOR. A STRAP IS ATTACHED TO ONE OF THE MOTOR BOLT HOLE GROMMETS TO PROVIDE A GROUND FOR THE SUPPRESSOR. THE MOTOR IS PROTECTED BY AN AUTOMATIC RESET TYPE CIRCUIT BREAKER LOCATED ON THE MOTOR BRUSH HOLDER ASSEMBLY. A FUSE LOCATED IN THE FUSE BLOCK PROTECTS THE VEHICLE WIRING. REFERRING TO FIGURE 10, NOTE THAT THERE ARE FOUR TERMINALS WHICH ARE NUMBERED FOR ILLUSTRATIVE PURPOSES. THE FUNCTION OF EACH TERMINAL IS COVERED IN THE EXPLANATION THAT FOLLOWS. WIPERS ARE EQUIPPED WITH LOCKING TYPE CONNECTORS FOR ATTACHING VEHICLE WIRING AND CARE SHOULD BE USED WHEN DISCONNECTING WIRING FROM WIPER. AS SHOWN IN FIGURE 10, THE WIPER MOTOR HAS THREE BRUSHES WHICH ARE REFERRED TO AS COMMON, LOW SPEED AND HIGH SPEED. WHEN THE IGNITION SWITCH IS ON, 12V PLUS CIRCUIT IS COMPLETED TO BOTH THE LOW AND HIGH SPEED FIXED CONTACTS IN THE COLUMN SWITCH. THE LOW AND HIGH SPEED BRUSHES ARE CONNECTED TO THE COLUMN SWITCH THROUGH TERMINALS 2 AND 1. THE ARMATURE IS GROUNDED THROUGH THE COMMON BRUSH VIA THE GROUND STRAP CHART

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.