4WD INDICATOR LIGHT WIRING R&R K/1500-3500 SERIES P/U TRUCKS
Subject: PRODUCT CAMPAIGN 91C07 4WD INDICATOR LIGHT WIRING
Model and Year: 1991 CHEVROLET K 1500-3500 SERIES PICKUP TRUCKS (OSHAWA ASSEMBLY CENTRE ONLY)
TO: ALL CHEVROLET DEALERS
General Motors has determined that on certain 1991 Chevrolet K 1500-3500 Series Pickup Trucks built at the Oshawa Assembly Centre the front axle indicator light may not work as intended. An electrical feedback condition may allow the light to remain on when the transfer case is shifted from four-wheel drive (4wd) to two-wheel drive (2wd). If the vehicle continues to be operated in 2wd, this feedback condition will fail the front axle engagement switch causing the light to go out. When the vehicle is again placed into 4wd, the light will not go on and the rear wheel anti-lock (RWAL) system will remain enabled (it is normally disabled in 4wd). If the RWAL is activated while in 4wd, a diagnostic code "5" will be set in the RWAL module. This disables the RWAL function and causes the brake warning light on the instrument panel to illuminate and remain on. To correct this condition, dealers will install a new wiring harness and front axle engagement switch on all involved vehicles.
VEHICLES INVOLVED
Involved are certain 1991 Chevrolet K 1500-3500 Series Pickup Trucks built at the Oshawa Assembly Centre within the following VIN breakpoints:
PLANT YEAR MODEL PLANT CODE FROM THROUGH ---- ------- ------ ----- -------- -------- 1991 K-Truck Oshawa "1" M1142020 M1142448
Involved vehicles have been identified by Vehicle Identification Number Computer Listings. Computer listings contain the complete Vehicle Identification Number, owner name and address data, and are furnished to involved dealers with the campaign bulletin. Owner name and address data furnished will enable dealers to follow-up with owners involved in this campaign.
These listings may contain owner names and addresses obtained from State Motor Vehicle Registration Records. The use of such motor vehicle registration data for any other purpose is a violation of law in several states. Accordingly, you are urged to limit the use of this listing to the follow-up necessary to complete this campaign. Any dealer not receiving a computer listing with the campaign bulletin has no involved vehicles currently assigned.
OWNER NOTIFICATION
There will be no owner letters sent out for this campaign as it is expected that the vehicles involved are still in now vehicle inventory and should be repaired prior to retail sale. If a unit has been retailed, in order to maintain customer satisfaction, contact the owner immediately and arrange to correct this condition on his or her vehicle.
DEALER CAMPAIGN RESPONSIBILITY
Dealers are to service all vehicles subject to this campaign at no charge to owners, regardless of mileage, age of vehicle, or ownership, from this time forward.
Whenever a vehicle subject to this campaign is taken into your new or used vehicle inventory or it is in your dealership for service in the future, you should take the steps necessary to be sure the campaign correction has been made before reselling or releasing the vehicle.
Owners of vehicles recently sold from your new vehicle inventory are to be contacted by the dealer, and arrangements made to make the required correction according to instructions contained in this bulletin.
PARTS INFORMATION
Parts required to complete this campaign will be shipped directly to involved dealers by Chevrolet Motor Division on a no charge basis via next day delivery. Any questions pertaining to parts shortages, etc. should be directed to the Chevrolet Dealer Assistance Center.
DO NOT ORDER FROM GENERAL MOTORS SERVICE PARTS OPERATION (GMSPO).
Quantity/ Part Number Description Vehicle Application ----------- -------------- --------- ---------------- 12088249 Wiring Harness 1 K 3500 (1 Ton) & MT1 (4L80E)
12088250 " " 1 K 2500 (3/4 Ton) & MT1 (4L80E)
12088262 " " 1 K 1500-2500 (1/2 & 3/4 Ton) & MD8,MG5,MT8 or M20
12088263 Wiring Harness 1 K 3500 (1 Ton) & MT8 or M20
15552842 Front Axle 1 K 1500-2500 (1/2 & Engagement Switch 3/4 Ton)
15638264 " " K 3500 (1 Ton)
SERVICE PROCEDURE
INSPECTION:
----------- Raise truck on hoist and check white 4-way connector at front axle for wire colors (Figure 1, page 5). If wire in cavity "A" is brown, the truck has the correct wiring harness. If correct, lower truck and proceed to step 21.
If wire in cavity "A" is blue, harness and front axle switch must be changed. Lower truck and proceed to "Repair" section below.
REPAIR:
------ 1. Prepare truck; disconnect negative battery cable.
2. Remove clamp on right frame rail which holds battery cable and wiring conduit for the front axle switch.
3. For vehicles with dual rear wheels (RPO R05) only, disconnect relay connector from inside convenience center at right side of truck. Relay connector will be the one toward the driver's side (Figure 1, page 5).
4. Disconnect engine wiring harness connector behind the engine (Figure 2, View A, page 6) . This is a purple wire behind the engine located approximately at the edge of the transmission bell housing. This connector is more accessible from under the hood, but it is viewed easier from under the truck. Thus you may want to raise the truck before disconnecting this connector.
5. Raise truck on hoist.
6. Disconnect white 4-way connector from front axle engagement switch, and disconnect the connector to the actuator (located directly next to the white 4-way connector).
7. Open harness clip which is bolted to transmission bell housing just above starter heat shield (Figure 2, View A) , and open harness clip located on top right of transfer case (Figure 2, Main View, page 6).
8. Disconnect the following three connectors on left side of transmission (Figure 2, Main View, page 6) one connects to the indicator lamp (attached to the floor pan) , one to the front side of the transfer case, and one to the output speed sensor (a brass colored piece on the side of the transmission).
For trucks with MT1 (4L80E) transmissions, there will be an additional two pin connector extension from the output speed sensor which should be disconnected.
9. Disconnect harness from back of transfer case at vehicle speed sensor (Figure 2, View B, page 6) . For trucks with dual rear wheels (RPO R05) there is an additional connector with a large red wire to be disconnected .
10. Fabricate a pull wire about four (4) to five (5) feet long, and attach it to front axle end of harness.
11. Pull harness through the starter heat shield from transmission side of truck, leaving pull wire running through the heat shield.
12. Connect new harness to pull wire on front axle connector side of harness and tape over the two connectors to allow them to pass through the heat shield easily.
13. Pull new harness through heat shield toward the front axle side.
14. Remove and replace front axle engagement switch.
15. Reconnect harness to front axle engagement switch and actuator, and tie strap the harness to the starter wires at the bottom of the starter heat shield.
NOTICE: Harness must be looped under battery cable harness on frame rail to prevent harness from touching the exhaust manifold (Figure 1).
16. Connect the connectors to left side of transmission and rear of transfer case. Reclip harness to clip at top right of the transfer case and to the clip bolted onto transmission bell housing.
17. For trucks with dual rear wheels (RPO R05), attach pull wire to relay connector, and feed pull wire up through truck to assist in retrieving this connector.
18. Lower truck, and reconnect engine wiring harness connector (purple wire) and relay connector (if equipped with dual rear wheels - RPO R05) located in the convenience center.
19. Refasten clamp on right frame rail, keeping harness routed under battery cable and free from exhaust manifold.
20. Reconnect battery and road test truck to verify proper operation of 4wd indicator lamp.
21. Install Campaign Identification Label.
CAMPAIGN IDENTIFICATION LABEL
Each vehicle corrected in accordance with the instructions outlined in this bulletin will require a "Campaign Identification Label". Each label provides a space to include the five (5) digit dealer code of the dealer performing the campaign service. This information may be inserted with a typewriter or a ball point pen.
Each "Campaign Identification Label" is to be located on the radiator core support in an area which will be visible when the vehicle is brought in for periodic servicing by the owner. Apply "Campaign Identification Label" only on a clean, dry surface.
CLAIM INFORMATION
Submit a Product Campaign Claim with the information indicated below:
FAILED PART PARTS CC-FC LABOR LAB OTH NET REPAIR PERFORMED PC NO. ALLOW OP HRS HRS AMT ---------------- -- ----- ----- ----- ----- ---- --- --- Inspect - Correct Wiring Harness Already Installed SK-00 V6490 0.2 0.1 $00.00 No Further Action Required
Inspect And Install New Wiring Harness And Front Axle SK-00 V6491 0.7 0.1 $27.00 Engagement Switch
* Campaign Administrative Allowance. Add 0.2 hours for vehicles equipped with dual rear wheels (RPO R05) as needed after obtaining Wholesale Authorization "E".
** The $27.05 identified in the "Net Amount" column represents 30% of dealer net for parts furnished by Chevrolet Motor Division and used in conjunction with labor operation V6491.
Dealers will automatically receive the correct labor based on the labor operation performed.
Refer to the Chevrolet Claims Processing Manual for details on Product Campaign Claim Submission.
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.
