One problem related to tail light has been reported for the 2005 GMC Envoy. The most recently reported issues are listed below.
The contact owns a 2005 GMC Envoy. He stated that the headlights, dashboard lights and rear lights shut off while driving approximately 35 mph or various speeds. The high beams immediately activate when the headlights shut off which distracts drivers. The failure mileage was 28000 and the current mileage was 58000.