I can’t figure out how to get the heater box out. I removed one nut from the fire wall, 1 from in the cab and I broke two tabs that are on each side of this bolt. I can’t find another bolt anywhere but it appears that there is one more bolt left. I think it’s located towards the driver side of the box.

Help!!!!

Is the heater core leaking?

Did you buy a haynes or chiltons repair manual?

What I've heard on the newer Blazers you have to take the dash almost completely apart. Real tough job there.

I have the Chiltons which is nearly worthless...
It tells me to "remove heater core box"

It is leaking.

I already have the dash completely out.

You have to take the dashboard apart.
The final bolt is behind the glove box.
You will need to remove the radio to be able to reach behind it and shine a light in and you will probably have to use a 90degree socket behind the glove box from underneath to reach it.

Hope this helps.
NitrousPC

Might read through this info for the earlier models. Dash is somewhat different but the heater may be pretty much the same. http://www.sytyarchives.com/howto/viewarticle.php?article_name=heater_core.php&dir=climate_controls