Have a 2002 silverado and my abs and brake light stays on

ABS is only activated when traction is limited. they do not activate during normal usage. I would have your abs system checked as the light only comes on when errors are detected. It could be just a sensor or sticking light

The warning lights are indicating a malfunction has been detected in either the sensing or actuation portion of the ABS system. Your base brakes will function normally but in the event of an ABS controlled stop on an "icy" or "slippery" stretch of road were the ABS system would take over to prevent a skid, that automatic system will not function.
Have the vehicle scanned for trouble codes to find out which portion of the system has malfunctioned.
Good luck,
Regards,

You may think they are fine. Did you check the brake fluid level? If its OK, there is a problem with the ABS brakes.