On my 1999/2000 Blazer ZR2 there is no heat from the heater at all.
Having said that there is just enoght heat to clear the windshield for ice if there is not to cold outside but the inside of the car is really cold.
Any here on the forum knows what can cause this?

To be honest i have fixed this problem so the car is nice and warm so i am just posting this question since i am pretty sure what you will answer
This thread might also be useful for others that have this problem

 

There can be several causes for this. What was your fix?

 

I would say backflushing the heater core is the fix

 

For me when I lost heat, it was the blend-door actuator that broke.