I have a 2002 envoy SLT and the exterior rear hatch light and the two rear tail lights stay on. This is after I have exited the vehicle, removed the key, insured the parking brake is off & no exterior light delay is set.I have locked/unlocked the vehicle using the key remote still no change. Set and and released the parking brake a few times to make sure it was not sticking and still these three rear lights stay on. All doors & rear hatch are securely closed still stay on. It is only the rear lights. Where do I look/ what do I do?