One problem related to brake light on has been reported for the 1999 GMC Safari. The most recently reported issues are listed below.
Anti lock brake light is on. Replaced all worn pads and shoes. Light will not reset. The van will not pass utah safty inspection with light on. Not sure of how safe the van is. GMC has a known track record of safty issue with their anti lock brakes. They risk families health by not resolving the known issue with their anti lock brake systems.