GMC Envoy--Headlight problems and possible fix
To all the people that are having problems with headlights not working on their 2004 (and I imagine other years as well) Envoy the fix is simple. There is a fuse box under the hood. Look in your owners manual and look for 'headlight control module.' It should be 45 in the book. To make sure that's the problem, swap out 46 with 45. They are the same. If your lights work, then you know it's the module. Most auto part stores don't have them, but I got one at the dealer for just under $60. FYI, it's also called a headlight relay. Hope this helps!