For 1990-2009 cars

# ANTI- LOCK BRAKE MOTOR P/N'S & REPAIR PROCEDURE

#### VEHICLES AFFECTED: 1986 'C' SERIES AND STE

There have been some comments received involving a blown 3OApump motor fuse on anti-lock brake systems. The condition causing this in some cases has been an intermittent problem within the pump motor. If there is brake fluid on the outside of the pump motor in the area of the connector, this is most likely the case. The following parts should be replaced:

Part Number

pump W/motor 25528401 switch, pump and pressure warning 25530882

If you do not observe brake fluid on the outside of the pump motor case, determine the current draw of the motor during operation. Normal current draw is approximately 24 amps. Depress the brake pedal until the pump motor runs and observe the current draw a number of times. If the current draw on occasion is steadily over 30 amps, the pump and switch should be replaced even though the fuse may not blow.

There has also been some comment involving the electrical connector to the pump motor. If after exchanging the motor, you have problems getting the system to pump up, check the wiring in the connector. The red wire should be in cavity one (1) and the black wire in cavity two (2). Also, when properly connected, the red wire is up or above the black wire. If these leads are reversed, the motor will run backwards and will not pump.

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.