89 s10 Heater Issues

[hacking4kix]

Ok well I am new here and I came across this just surfing around. I know a little about cars and can do anything if someone helps me or tells me what to look for etc.. Now is it was a tv I can fix that in a heartbeat, anyway I have an issue with my 89 s10 Blazer.
The AC works and will blow through the vents not really strong but good enough, however when I hit the heater I can hear air, but nothing blows out of the vents and when I hot the defrost it just blows cold.
The car is an 89 s10 blazer 4wd and 4.3 I replaced the heater core in the car I would say a year and a half ago..and someone told me it might be a vaccum line,but I have no idea where it is, I was also told could be a relay or a fuse? Sorry but if anyone can help me that would be great...Thank You

[ricksza]

Sounds like you have a couple of issues.

First no air from the vents: when the heater control has no vacuum, it defaults mostly to the defroster. I would check at the vacuum tank on the left front inner fender well. If ok there, check at the heater control.

Second no heat: the temperature is controlled by cable. It goes from the heater control to the heater box right behind the glove box. I would loosen the heater control from the dash and see if the cable is connected and moving. If it is, remove the glove box and check from that end. The other possibility is that the heater core has an air pocket caused by low coolant.

[hacking4kix]

ok so i will check on all of that and let you know what i find, if its an air pocket how is that removed?

[ricksza]

To get rid of an air pocket, you have to make sure the fill area is the highest point of the cooling system. On some trucks, that means raising the front end up to two feet. I've had luck just removing the upper heater hose and filling it up directly with a funnel.