2004 Chevy Impala 6 cyl Front Wheel Drive Automatic 80000 miles
My Impala has several things wrong with it and I feel it's some sort of electrical short. The traction control light and abs light are coming on all the time. Just before the car stops, the brake pedal vibrates as if the abs is engaged. This stops at times and the warning lights go out. Also, the heater fan works only some of the time. When I start it the heater/ac fan is working most of the time, but when I hit a bump, it goes off and doesn't come back on. Is this an engine compartment problem or something much more complicated?
You really need to ask 2 separate questions for the 2 different problems. It's get way too confusing to follow this way. I will address the ABS problem.
What sounds like is happening is one of the wheel speed sensors is dropping in and and out intermittently. The pedal vibration your feeling is the ABS system actually activating because one of the sensors is reading inaccurately and the ABS computer reads that as a brake lockup and the system activates to release that wheel. You will actually need a professional scan tool that has the ability to take frame by frame snapshots of the ABS data to determine which sensor is doing it.