SERVICE MAN. UPDATE SEC.8 CELL 104 DAYTIME RUNNING LIGHTS

SUBJECT: SERVICE MANUAL UPDATE - SECTION 8, C RUNNING LIGHTS (T61)

MODELS AFFECTED: 1990 SKYLARKS WITH T61 (CANADIAN DAYTIME RUNNING LIGHTS)

THIS BULLETIN HAS BEING REVISED TO INCLUDE DIAGNOSIS CHARTS. PLEASE DISCARD BULLETIN 90-8-20.

The above vehicles built for sale in Canada, are affected by GM of Canada recalls and/or running production changes for the Daytime Running Lights (DRL) circuit and module.

The following vehicles built for sale in Canada are involved in GM of Canada recalls:

Through and Year and Model Plant Beginning Including ----------------- ------------- --------- --------- 1990 Buick Skylark Lansing-North LM000005 LM033601

The following pages contain revised information for the 1990 Skylark service manual Section 8A cell 104, "Daytime Running Lights (T61)". These revised pages are valid for 1990 Skylark vehicles built after the production change or those which have had the GM of Canada, daytime running lights, recall campaign previously completed.

Please update your 1990 Skylark service manual with the following information.

DAYTIME RUNNING LIGHTS (T61)

A: DAYTIME RUNNING LIGHTS (DRL) MODULE TEST (TABLE 1)

Measure: TEST LAMP

At: DAYTIME RUNNING LIGHTS (DRL) MODULE CONNECTOR (Disconnected)

Conditions:

---------- - Ignition Switch: RUN - Park Brake: Released - Light Switch: OFF

Connect Between Correct Result For Diagnosis ---------------- -------------- ------------------------------ A (ORN) & Ground Lamp Lights Check/repair ORN (140) wire, In-line fuse, and RED wire for an open or short to ground (see schematic). (BRN) & Ground Lamp Lights Check/repair BRN (250) wire, In-line Fuse, and BRN (50) wire for an open or short to ground (see schematic). C (TAN/WHT) & Ground Lamp Lights See Brake Warning System, page 8A-41. A (ORN) & F(BLK) Lamp Lights Check/repair BLK (150) wire for an open. A (ORN) & DRL Case Lamp Lights Check/repair BLK (150) wire and Ground Wire (BLK) ground G101 for open.

- Headlight Switch: ON - Headlight Dimmer Switch: HI ------------------------------ D (LT GRN) & Ground Lamp Lights Check/repair LT GRN wire for an open or short to ground. - Park Brake: Applied --------------------- C (TAN/WHT) & Ground Lamp off See Brake Warning System, page 8A-41.

- If all voltages are correct go to table 2

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.