If your 1999 Buick Regal has a TPMS (it likely doesn't have a direct TPMS; it may have an indirect system based on wheel speed sensors), and it's showing a low-pressure warning, you need to:
1. Inflate the tires: Use a reliable tire pressure gauge to inflate your tires to the correct pressure (found on a sticker inside the driver's side doorjamb or in your owner's manual).
2. Drive the car: After inflating the tires to the correct pressure, drive the car for a short distance (a few miles). The TPMS sensor should detect the increased pressure, and the warning light will typically turn off automatically.
3. If the light remains on: If the warning light stays on after driving and properly inflating your tires, there might be a problem with the TPMS sensors themselves, a faulty sensor, or a problem with the system's wiring. You'll need to take your car to a mechanic for diagnosis and repair.
If your 1999 Buick Regal *doesn't* have a TPMS, there's nothing to reset. You'll simply need to check and adjust the tire pressure yourself using a gauge.
