we replaced 2 freeze plugs is there a third one and do you know where it is

thanks do you no where the others are by chance?

Knowing what engine is in the van might be helpful. There's only 4 different engines.

the engine is a 3.3 engine

There are 8 expansion plugs for the cooling system. That's according to Dorman Corp. That is why you need to have the cooling system pressure tested.