HEADLAMP/WIPER/SEAT/MIRROR WINDOW SWITCHES REVISED

MODELS AFFECTED: 1986 BUICK RIVIERA

Some 1986 Riviera service replacement body switches with electroluminescent backlighting have been unavailable or difficult to obtain due to short supply. Service part supplies have been replenished and these switches are now available through GM Service Parts Operations (GMSPO) using the following part numbers:

1986 1986 1987 Old P/N New P/N P/N Description ------- ------- ---- ----------- 25525943 1645493 1640028 Headlamp Switch With Twilight Sentinel

25525944 1645494 1640029 Headlamp Switch w/o Twilight Sentinel

25525945 1645495 1640834 Windshield Wiper Switch w/Rear Defog

25525946 1645496 1642271 Windshield Wiper Switch w/o Rear Defog

1636498 1636498 1642275 Electroluminescent Inverter for Headlamp & Wiper Switches

20645520 1645508 20676242 Six-way Passenger Seat Switch

20645521 1645509 20676243 Six-way Driver Seat switch

20625421 20625421 1642276 Electroluminescent Inverter for Seat Switch

20693949 1645511 20676244 Remote Outside mirror Switch

20463712 1645510 20676245 Two-button Window Switch Mounted on Console

1636499 1636499 1642274 Electroluminescent Inverter for Mirror and Window Switches

When servicing a 1986 Riviera, perform the following checks before replacing a switch or inverter:

1. Check the last three digits of the seven or eight digit numerical part number stamped on the switch or inverter being replaced. Some 1986 Rivieras may have been serviced in the past with 1987 model parts because of 1986 switch shortages.

2. If the last three digits of the part number stamped on the switch or inverter match the last three digits of the 1987 part number listed in this bulletin, replace the switch or inverter with the 1987 style part. Be careful when checking the last three digits of the stamped part number. In some cases, the leading digits are physically stamped into the part while the trailing digits are stamped in ink. In other cases, the leading digits and trailing digits are physically stamped into the part; but the trailing digit(s) were stamped separately, and thus appear slightly offset from the leading digits. Find and check the seven or eight digit numerical part number.

3. After installation, check the switch backlighting intensity. If the switch backlighting is too bright or too dim compared to the other backlit components, check the last three digits of the part number stamped on the affected switch and its invertor.

4. The last three digits of the part number on the switch and inverter should indicate that both are 1986 part numbers or both are 1987 part numbers as listed in this bulletin. 1986 switches are not compatible with 1987 invertors and vice-versa.

For invertor location and switch backlighting diagnosis, see Section 8A-88 of the appropriate Buick Service Information Manual.

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.