[rshadd]

A new BCM will require programming.

2004 & 2005 are different part numbers...

http://parts.nalleygmc.com/showAssembly.aspx?ukey_assembly=436760&ukey_product=2863616

 

[rshadd]

I'm not sure, but I would think the BCM's are year specific and the programming is VIN specific.

Why do you think you need a new BCM?

 

[rshadd]

How old is your battery? A lot of those issues are cause by a weak battery.