Service Procedure

During servicing, each suspect push-pull headlight switch must be inspected.. If the switch is not within the range of suspect date codes, it need not be replaced. See the Inspection Procedure for the inspection method and range of suspect date codes. Disassembly and assembly procedures can be found in the following applicable Truck Service Manuals:

1985 S/T15 X-8529 Section 8B-16
1985 P25-35 X-8532 Section 8B-16
1986 C/K & G X-8632 Section 8B-24
1986 Medium Duty X-8433 Section 8C-4
1986 Heavy Duty X-8534 Section 8C-5

Figure 1:

INSPECTION PROCEDURE After removal of the Headlight Switch from the Instrument Panel, refer to the illustration to locate and identify the date code. The four-digit date code will appear the same on any switch regardless of the model usage or part number.
If the date code is 0015 or between the range 9235 through 9305, replace the switch using the correct part number per the Parts Information section. (This represents switch manufacturing dates of September 23, 1985 through and including October 1, 1985. If the switch is not within the suspect date codes, reconnect the existing switch. Reassemble the Headlight Switch per the applicable Service Manual instructions.

PARTS INFORMATION

Parts are to be obtained from the Warehousing & Distribution Division of General Motors (WDDGM). To ensure that these parts will be obtained as soon as possible, they should be ordered from WDDGM on a C.I.O. order with no special instruction code, but order under an advise code (2).

Part
Model Number Description Quantity

S/T15 1995217 Headlight Switch 1
C/K15-25-35 1995216 Headlight Switch 1
G-Van 1995216 Headlight Switch 1
P25-35 1995216 Headlight Switch 1
C5-6-7, B6, P6, 1995194 Headlight Switch 1
J8-9, D9

WARRANTY INFORMATION Dealers should submit an accurately filled out Warranty Repair Order on each vehicle completed under this campaign.

Labor *Time
Operation AllowTrouble
Number Description ance Code

V3260 Headlamp Switch S/T 0.9 Hr. 96
Inspect Only C/K 0.3 Hr.
G & P 0.4 Hr.
C5-6-7, B6, 0.3 Hr.
P6, D9
J8-9 0.4 Hr.

V3262 Headlamp Switch S/T 0.9 Hr. 96
Inspect& Replace C/K 0.3 Hr.
G & P 0.4 Hr.
C5-6-7, B6, 0.3 Hr.
P6, D9
J8-9 0.4 Hr.

*For dealer to receive Administration Time Allowance associated with this campaign, add 0.1 hour to the Labor Operation Time Allowance.
CAMPAIGN IDENTIFICATION LABEL

Each vehicle modified 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 ballpoint 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 oudined in Section V of your dealership's "GMC Truck Claims Processing Manual" #SD8519.
VEHICLES INVOLVED

In addition to the vehicles specified in Bulletin 86C-04, the following units should be included.

Model
Year Model Plant From Through

1986 P3 Detroit Assembly G3502163 G3502553
G Van Scarborough G4518889 G4520570
Lordstown G7511905 G7512484
C/K Janesville GJ521261 GJ522642
Flint #1 GF721388 GF722421
Flint #2 GF520150 GF521445
St. Louis GS520961 GS522584
Oshawa G1527436 G1529915

INSPECTION PROCEDURE

1986 GMC vehicles indicated above require a different inspection procedure from that described in Dealer Product Campaign Bulletin 86-C-04. If the alphabetically marked headlight switch cavity has either a "D" or an "M" identified, the switch must be replaced. The headlight switch cavity is on the opposite side of the switch from the date code indicated in 86-C-04.

HEADLIGHT SWITCH CAVITY:

1. After removing the headlight switch from the instrument panel, refer to the illustration to locate and identify the cavity code.
2. If the cavity code is a "D" or an "M" replace the switch using the correct part number in the Parts Information section. If the switch does not have "D" or "M" codes, reconnect the existing switch.

3. Install the Campaign Completion label on a clean dry surface of the radiator core support.
Truck & Bus Group
GMC Truck & Coach Operation General Motors Corporaton 31 Judson Street Pontiac, Michigan 48058
Dear GMC Truck Owner:

This notice is sent to you in accordance will the requirements of the National Traffic and Motor Vehicle Safety Act.

General Motors has determined that a defect which relates to motor vehicle safety exists in some 1985 S/T15 and P25-35 model light duty trucks and 1986 C/K, G-Van, Medium Duty and Heavy Duty model trucks.

The push-pull headlight switch might have been manufactured with electrical contacts which allow an intermittent headlight circuit. An intermittent circuit could cause the headlights to flicker or suddenly go out. Sudden loss of the headlights under severe weather or nighttime driving conditions could reduce driver visibility which might result in a vehicle crash without prior warning.

Until you have had an opportunity to have your GMC truck corrected, you should be alert for signs of an intermittent headlight circuit. For example, you might experience flickering headlights or temporary delay when you pull the headlight switch "ON."

To prevent this condition from occurring, please contact your GMC Truck dealer on or after the date shown below to arrange a service date to have your vehicle inspected. Your dealer will check the headlight switch. If necessary, the switch will be replaced. This service will be completed at no charge to you.

Instructions have been sent to your GMC Truck dealer. It is estimated that parts will be available to your dealer on May 8, 1986. The labor time necessary to check the headlight switch and replace it if necessary, is 35 minutes. Please ask your dealer if you wish to know how much additional time will be needed to process your vehicle.

Your GMC Truck dealer is best equipped to obtain parts and provide service to ensure your vehicle is corrected as promptly as possible. However, if you take your vehicle to your dealer on the agreed service date and they do not remedy this condition on that date or within five days, we recommend you contact your nearest GMC Truck Zone Office, either in person or by telephone. The Zone Office will assist you and your dealer in getting your vehicle corrected. The locations and telephone numbers of the Zone Offices are listed in your Owner's Manual.

After contacting your dealer and the Zone Office, if you are still not satisfied that we have done our best to remedy this condition without charge within a reasonable time, you may wish to write the Administrator, National Highway Traffic Safety Administration, 400 Seventh Street, S.W., Washington, D.C. 20590, or call 800-424-9393 (Washington, D.C. residents use 426-0123).

The enclosed owner reply card identifies your vehicle. Presentation of this card to your dealer will assist them in making 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 safety and continued satisfaction with our products.

GMC TRUCK GENERAL MOTORS CORPORATION