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CAMPAIGN: ENGINE HARNESS ECM CONNECTOR CRACKED TERMINAL

MODELS: 1987 S/T 15 TRUCKS EQUIPPED WITH 2.5 L ENGINES (RPO LN8)

General Motors has determined that some 1987 GMC S/T 15 model trucks equipped with 2.5L engines (RPO LN8) may have been built with an engine electrical harness which has a cracked wire terminal on a jumper wire in the ECM connector. As a part of the fuel injector signal circuit, if the terminal breaks and causes an open circuit, this will allow the engine to crank but not start.

To prevent this condition from occurring it will be necessary to replace the jumper wire, which has terminals attached.

VEHICLES INVOLVED

Involved are certain 1987 GMC S/T 15 trucks equipped with 2.5L engines (RPO LN8) built within the following VIN breakpoints:

PLANT FROM TO ----- ---- -- Pontiac H0505825 H0507243 Moraine H2507772 H2511308 Shreveport H8511924 H8513235

The specific vehicles involved in this campaign have been identified by Vehicle Identification Number Computer Listings. These listings are furnished to all involved dealers with the campaign bulletin.

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 ensure 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.

If no owner's name and address were available to GMC Truck Division at the time of campaign initiation, the dealer will determine the owner's name and address from the dealership sales records. Please provide this information directly on the second copy of the listing next to the applicable VIN so that our records may be updated and the appropriate notification mailed to the owner. This second copy should then be submitted to the address listed below in the previously supplied yellow campaign envelopes.

GMC Truck Division General Motors Corporation 101 Union Street Plymouth, Michigan 48170

OWNER NOTIFICATION

Owners will be notified of this campaign on their vehicles by GMC Truck Division (see copy of Owner Letter included with this bulletin). A listing of owner names and addresses has been furnished to the involved dealers to enable dealers to follow up with owners involved in this campaign. This listing 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 this campaign.

SERVICE PROCEDURE

A jumper wire will be furnished "no charge" for each vehicle by GMC Truck Division. Parts will be shipped directly to the involved dealers. Use the following instructions to install the new jumper wire.

In order to remove micro-pack terminals from the connector, a terminal removal tool will be required to perform this repair. Proper tool is Kent-Moore J-33095 or Burroughs BT-8234-A.

1. Disconnect negative battery cable.

2. Locate the ECM under the instrument panel on the passenger side of the vehicle. Disconnect both connedors from the ECM.

3. Locate and disconnect the instrument panel wiring interconnect taped to ECM harness.

a. Locate the 151 Jumper wire terminals (.80 gage black) that are side by side in cavities D-9 and D-10 in the center of the 32-way ECM connector (with gray secondary locks), Figure No. 1A.

4. Remove the gray comb secondary lock (using a pick) retaining the 151 wire terminal by releasing the lock tangs on the outside of the ECM connector at both points A and pulling the secondary lock out of the connector (Figure No. 1B).

Removal of the 151 wire:

a. Grasp the wire seated in cavity D-9 and push the terminal to its forward most position.

b. Insert the micro-pack removal tool into the outside hole of the D-9 cavity (see Figure No. 2). Removal tool will depress the lock tang only while the terminal is in the forward most position in the cavity.

c. While holding the tool securely in place, gently pull on the wire to remove the terminal.

CAUTION:

To prevent damage to the connector:

A. Only use the micro-pack removal tool, J-33095 or BT-8234-A.

B. Do not apply excessive pressure to the removal tool.

C. Do not rock or angle the removal tool.

d. Remove the second end of the 151 wire by repeating steps 4A through 4C in cavity D-10.

Remove the 151 wire from the harness by firmly grasping both ends with pliers and gently pulling it out of the harness. Install the replacement wire as follows:

Orient the first terminal on the replacement wire so that the box side of the terminal is toward the center of the connector. Insert the terminal into cavity number D-9. A faint click will be heard as the terminal locks in place. Give the wire a light tug to insure it is seated.

Install the remaining end of the replacement wire into cavity D-10 following the above procedure.

Reinstall the secondary lock into the connector by inserting the teeth of the lock into the connector and pushing firmly until the lock legs snap into place.

Separate the two ECM connector branches. Fold the loop of the replacement wire toward the 32-way ECM connector and secure with plastic electrical tape.

Reconnect the two ECM connectors to the ECM.

Reconnect the instrument panel interconnect.

5. Reconnect battery cable.

PARTS INFORMATION

Jumper wires complete with terminals have been shipped directly to the involved dealers. If additional wires are required, contact your GMC Truck service representative.

PART NUMBER DESCRIPTION QUANTITY ------- ----------- -------- 12077137 Jumper Wire 1

WARRANTY INFORMATION

Dealers should submit a warranty claim for each vehicle completed under this campaign.

LABOR OPERATION *TIME TROUBLE NUMBER DESCRIPTION ALLOWANCE CODE --------- ----------- --------- ------- V4040 Replace 151 .5 hrs 96 jumper wire according to service procedure

*Add 0.1 hr. for administration time allowance

CAMPAIGN IDENTIFICATION LABEL

Each vehicle corrected in accordance with the instructions outlined in this Product Campaign 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 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.

ADMINISTRATIVE PROCEDURE

Procedures covering this campaign are outlined in Section V of your dealership's "GMC Truck Claims Processing Manual" #P8719.

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Dear GMC Truck Owner:

General Motors has determined that some 1987 GMC S/T 15 trucks equipped with 2.5L engines (RPO LN8) may have been built with an engine electrical harness which has a cracked wire terminal on a jumper wire in the ECM connector. As part of the fuel injector signal circuit, if the terminal breaks and causes an open circuit, this will allow the engine to crank but not start.

To prevent this condition from occurring it will be necessary to replace the jumper wire, which has terminals attached.

Instructions and parts for this correction have been sent to your GMC Truck dealer. Please contact your GMC Truck dealer to arrange a service date to have the wire installed at your convenience. The service will be performed at no charge to you.

The labor time to service your vehicle is approximately 30 minutes. Please ask your dealer if you wish to know how much additional time will be needed to process your vehicle. The enclosed owner reply card identifies your vehicle. Presentation of this card to your dealer will assist in completing the necessary correction to your vehicle in the shortest possible time. If you have sold or traded your vehicle, please let us know by completing the postage paid owner reply card and returning it to us.

We are sorry to cause you this inconvenience; however, we have taken this action in the interest of your continued satisfaction with our products.

GMC TRUCK DIVISION GENERAL MOTORS CORPORATION

87CO6 Enclosure


Object Number: 90604  Size: SF


Object Number: 83545  Size: FS


Object Number: 83544  Size: FS


Object Number: 83543  Size: FS

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.