Two problems related to brake light on have been reported for the 2000 GMC Sonoma. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2000 GMC Sonoma based on all problems reported for the 2000 Sonoma.
Shortly after I purchased my 2000 GMC Sonoma (VIN #1gtct19wxy8124176) I had a "low speed activation" of the abs. Some time later the brake warning light was activated. I took the truck to a GMC dealer and was told I had no problems, but they did replace the brake shoes. Ever since then the low speed activation would happen periodically. Recently, the problem has evolved to every day. And I believe this root problem is behind a lot of other brake problems I've had with this vehicle.
When traveling at highway speeds abs light comes on, and brake light on dash blinks although brakes are not being applied. Brake light will stop blinking if vehicle is slowed down, but the abs light will stay on until key is taken from ignition. Dealer has seen vehicle 3-4 times, and can not fix it.