1996 Chevy Lumina APV heating problem

my van was defrosting fine and heating fine. Then it would go off every now and then, now I am not getting any heat blowing out at all. What could be the problem?

What do you mean exactly? fan works and just cold air, no heat ?....or fan would not blow, dead blower, no air at all..?

I mean no air is coming out at all, no cold no hot. Not sure if it's the blower motor or not

When you place the fan select to "HI" can you here or feel the blower motor running ? It is under the right side dash.

Test blower motor by connecting 12V direct to the motor connector, in engine compartment: 1996 plastic body must have kept this original configuration:
http://www.avigex.ca/xport/heaterrelay.jpg
If motor ok, check high speed relay and socket . (all speeds are fed through the high speed relay).