Here's why:
* ABS System Interference: The ABS system is designed to prevent wheel lockup during braking. When the ABS light is ON, it usually indicates a malfunction *within* the ABS system. The system may be trying to engage, or its sensors/computer are misreporting, leading to erratic brake behavior.
* Hard Braking or No Braking: When the ABS module malfunctions, it can send incorrect signals to the hydraulic control unit which controls the pressure applied to your brakes. This results in inconsistent brake application. Sometimes you'll get full pressure (hard braking), other times no pressure at all (no braking).
* It's not just a light: The light isn't just a warning; it means the ABS is affecting your non-ABS braking. Your car's braking system isn't designed to function correctly without the ABS computer being operational.
What you should NOT do:
* Don't drive the truck. This is extremely dangerous. Erratic braking can lead to accidents.
What you SHOULD do:
1. Have it towed to a qualified mechanic or repair shop immediately. Do not attempt to drive the truck until it's fixed.
2. Explain the exact symptoms: Clearly describe how the brakes behave when the ABS light is on and off.
3. Be prepared for potential repair costs: Fixing ABS issues can be expensive due to the complexity of the system. It could involve replacing sensors, the ABS module, or even parts of the hydraulic system.
Ignoring this problem could lead to a serious accident. Get it checked out as soon as possible.