I have a 1998 blazer just today my climate control quit working here are the syptoms

1.Blows luke warm air no matter where temp wheel is set
2.a/c compressor comes on and pipes getting gold but no cold from grilles {worked awesome this weekend freeze ya right out}
3.position selector will not blow on floor top vents and windshield only

 

Sounds like its possibly a combination of problems. First, it sounds like you have lost vacuum to the HVAC controls. Second, you may have a problem with your blend door actuator (electronic). Both of which are fairly common problems and a few choice search terms should get you the information necessary to fix the problems.

 

ok i did some looking over things on the blazer it appears the damper blade in the heater box has broken off the shaft . i went under dash driver side i found 2 actuators and they both function as they should but the easy one to get to if you will seams to be broken the box shaft turns with vacuum but nothing chabges the upper diaghram is working properly but the lower outer must be busted i pulled the actuator off and turned it by hand the shaft feels like it may broken somewhere and airflow doesnt change when turned.

With that said i can live with no floor heat certainlt not worth dissmantling the whole dash for that

now onto my other problem with no temperature control after reading some threads it appears i may have a bad blend door actuator since i have no control of heat or cooling all actuators respond to controls and vacuum lines are ok

 

Got it working blend door just took a little tap and it started worhking

still no floor heat due to broken damper i beleive no biggie

still didnt have much for heat so i backflushed heater coil its smokin hot and the air is ice cold


sweat didnt cost me a dime thanks to other threads i searched through for info

 

Glad it was something easy on the blend door. That can be a challenge to remove, even more so if you have big hands.