I have a problem with my 1997 blazer. The engine light is usually always on. Sometimes the ABS anti-lock brake light will come on. When it does come on I sometimes hear a vibrating noise in the engine bay near the brake master cylinder area, and when the light comes on the transmission always stops working-will not shift gears at all or very badly when driving. I recently changed the brake fluid, and bleed the brakes twice thinking this could be the problem. The brake pedal feels really good after the fluid change. The old fluid was very dirty. This is a big problem as the truck tends to stay only in first gear when the light comes on. When I shut the truck off the light will go off and not come on again for a little while of driving. I think I have a bad transmission range switch-could this be related?