Why would my ABS Brake light come on and my speedometer start jumping when I’m in 2wheel drive and hit 30-40mph. And doesn’t do it in 4wheel hi or low?
The most common reason for the ABS Brake light to come on is when the brake fluid level is low. Since the brake fluid level moves around it may come on while moving up or down hills or on heavy acceleration or deceleration. As for the Speedometer jumping around, it is possibly a VSS- Vehicle Speed Sensor issue or a malfunction in the gauge cluster assembly. Gauge cluster issues are also common on these Chevy trucks