Figuring out exactly what's wrong with it is usually a good place to start.
Ring 07885203889 I got one couple of weeks back
Try this link. I have a 2004 Envoy and mine is doing it. http://forums.trailvoy.com/showthread.php?t=48777
The 2004 GMC Yukon-XL has 61.3 in. of rear hip room.
The 2004 GMC Yukon-XL has 39.1 in. of rear leg room.
The 2004 GMC Yukon-XL has 39 in. of rear head room.
The 2004 GMC Yukon-XL has 65.1 in. of rear shoulder room.
It is located under the second row seat
The rear track of the 2004 GMC Yukon-XL is 5 ft. 6 in. (66 in.).
You can locate the transmission fluid in your 2004 GMC Envoy by using the transmission fluid dipstick. The transmission fluid will be in the transmission fluid pan.
The 2004 GMC Yukon-XL has rear wheel drive.
Its your relay switch... change it out and it should work..
XL means extra large or extra long. It has room for a third row of seats.