[ssgharkness020147]

I read the rebuild instructions when mine went, like you said it doesn't look too bad. But, I was feeling lazy so I opted out. The thing you need to remember is that HVAC unit which needs to come completely out has the AC condenser in it, so the AC system needs to be purged. The HVAC unit itself is all glued together with a black RTV (like) sealant. I know in my case the mechanic hated that, being fragile plastic you need to be sure to be very careful when disassembling it. As far as a cross over part # goes, there is none. Either you get it from HUMMER, or you have one custom made. The core you currently have could probably be repaired by an competent automotive HVAC shop.