SUPPLE. INFLATABLE RESTRAINT SYSTEM WIRING REPAIR PROCEDURE
Model and Year: 1990 Y CAR WITH 5.7L (VIN CODE J, 8) ENGINES
The 1990 model year is the first year select Chevrolet vehicles will be equipped with Supplemental Inflatable Restraint (SIR) Systems. Throughout General Motors four different systems are utilized in total. Each system may appear the same, however, unique design differences require different service procedures for each. Considering these facts, it is extremely important that the correct service manual and service bulletin be used during diagnosis and repair if required.
The following Supplemental Inflatable Restraint (SIR) system wiring repair information applies to CORVETTE ONLY.
Special wiring repair procedures have been developed for use on the Supplemental Inflatable Restraint (SIR) System due to the sensitive nature of the circuitry. These specific procedures and instructions must be followed when working with SIR System wiring and wiring components (such as connectors and terminals). Some system components require replacement, while others may be repaired. Always follow the guidelines given below when working with SIR wiring.
WIRING REPAIR
When repairs to the SIR system wiring are made, always use the Crimp & Seal splices, crimping tools, and repair instructions supplied with Wiring Repair Kit J 38125-A. NO ALTERNATE REPAIR METHODS ARE ALLOWED. If the proper tools and/or components are not available, contact Chevrolet Technical Assistance to arrange for proper service of the SIR system.
When there is a reference made to the "DERM side of the harness" it means that part of a circuit's wiring which runs FROM the DERM TO the connector. When a reference is made to the "vehicle side of the harness" it means; that portion of a circuit's wiring which runs FROM a system in the vehicle TO the connection point with the DERM.
The following items may NOT be serviced; if they are damaged, the entire component, with its associated wiring, must be replaced.
1. DERM-to-SIR Coil wiring harness. 2. DERM-to-I/P Harness wiring harness. 3. DERM-to-Sensor Harness, both left and right sides. 4. DERM-to-Sensor Harness connectors. 5. Forward Discriminating Sensor wiring pigtail and connector, both left and right sides. 6. SIR Coil-to-DERM Connector. 7. SIR Coil-to-inflator Module Connector. 8. SIR Coil wiring.
The following items may be REPLACED:
1. The DERM-to-SIR Coil Connector half at the base of the steering column. This connector half (with wiring leads) is supplied in Kit J 38125-A, and should be replaced as an assembly. The SIR Coil-to-DERM Connector half, which mates with this connector, cannot be serviced; if it is damaged, the SIR Coil Assembly must be replaced.
2. Damaged terminals in either the DERM side or the vehicle side of the DERM-to-I/P Harness connector. If there is a problem with a terminal in these connectors (natural color; 10-way), back the damaged terminal out of the connector half, cut the wire, and splice in a new terminal-with-lead assembly. Terminal-and-lead assemblies are provided with Kit J 38125-A. Do not replace individual terminals by selecting one from the many terminals provided with J 38125-A; always use the prefabricated terminal-with-lead assemblies.
The following items may be REPAIRED:
1. The VEHICLE side of the I/P Harness wiring that connects to the DERM, but not the DERM-to-I/P Harness wiring. If the vehicle side of the I/P Harness is damaged, the wire should be repaired by splicing in a new section of wire of the same gauge size (.5, .8, 1.0, etc.). If the DERM-to-I/P Harness wiring is damaged, the DERM must be replaced. No DERM harness wiring can be repaired.
TERMINAL REPAIR KIT J 38125-A
Essential tool kit J 38125-A contains special "sealed splices" for use in repairing certain SIR system wiring. A special crimping tool, heat torch, and instruction manual for these splices are also included.
Two critical features of the sealed splices are a special heat shrink sleeve with sealing adhesive to produce an environmentally sealed splice and a cross hatched (knurled) core crimp to provide necessary contact integrity for the sensitive, low-energy SIR circuits.
Other Corvette-applicable items included in the kit are DERM-to-SIR Coil Connector Repair Kits, Connector Position Assurance (CPA) devices, used to maintain connection integrity on the DERM-to-SIR Coil and DERM-to-I/P Harness connections, yellow tape for retaping harnesses, and terminal-and-lead assemblies for repairing damaged terminals in the DERM-to-I/P Harness connectors.
Tool kit J 38125-A also serves as a generic terminal repair kit. The kit contains a large sampling of common GM electrical terminals and the correct tools to apply them to wires and remove them from connectors. The terminals in the kit are NOT to be used to replace damaged SIR system terminals; always use the prefabricated terminal-with-lead assemblies.
SIR WIRE REPAIR
Follow the steps listed below to make repairs using the sealed splices in kit J 38125-A.
STEP ONE: OPEN THE HARNESS -------------------------- If the harness is taped, remove the tape only as necessary to access the working area. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing stores). The crimp and seal splice sleeves may be used on all types of insulation except tefzel and coaxial and may only be used to form a one to one splice.
STEP TWO: CUT THE WIRE ---------------------- Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches, or connectors.
STEP THREE: STRIP THE INSULATION -------------------------------- If it is neccessary to add a length of wire to the existing harness, be certain to use the same size as the original wire.
To find the correct wire size, either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in your wire stripper and work down until you get a clean strip of the insulation. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section.
STEP FOUR: SELECT AND POSITION THE SPLICE SLEEVE ------------------------------------------------ Select the proper splice sleeve according to wire size. The salmon sleeve and red crimp nest should be correct for all approved SIR repairs on Corvette. The splice sleeves and tool nests are color coded.
Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop.
The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest.
STEP FIVE: INSERT WIRES INTO SPLICE SLEEVE AND CRIMP ---------------------------------------------------- Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice.
STEP SIX: SHRINK THE INSULATION AROUND THE SPLICE ------------------------------------------------- Using the heat torch apply heat where the barrel is crimped. Gradually move the heat barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved.
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.
