where are the main grounds im guessing you mean more then whats on the battery... also when i bought the care there was a bunch of recepts for work done in the car on the back of one it said front wheel bearings is bad they are a hub assembly with an abs wire when one goes bad it will shut abs& tracktion system off but im not sure where ths was from or if the wheel bearing got fixed but im assuming id know it if my wheel bearings were still bad