No Heat, A/C on constantly

The actuator seems to be operating correctly (no broken gear). The vacumn diaphram operates, it just blows cold even when I turn control to hot side.
Any ideas....any one else have this problem? I was wrong about the A/C being on constantly, I must not have waited long enough for it to cut off.

99 blazer

I found most of the problem with the lack of heat. Core was stopped up. I bought 6 foot of 5/8 heater hose and 6 foot of 3/4 heater hose. I removed the existing end of heater hoses at heater core and replaced them with the long ones I bought. I then place one end into a tall kitchen trashcan. I connected a garden hose into the other and flushed out the blockage. I then changed the direction and did the same thing again. I continued going back and forth until water came out clean. I still dont think I have as much heat as I should. But I do have heat now! Might need to get the whole system flushed.

Sounds like the Dexcool got gummed up. What engine does this Blazer have? Does it have the pressure cap on the radiator? If so you can't use Dexcool.

What you want to do is get a Prestone flush-T and follow the directions for it. You also want to get a bottle or two of radiator flush. (It might help if you can hook your water hose up to your hot water outlet from say your washing machine. Crank your water heater on max a few hours ahead of time so you won't run out of hot water.) The reason I suggest running hot water through it is because it will clean better and you'll be able to save time by running hot water through the flush-T after running the engine hot with the radiatir flush without having to wait for the engine to cool down as much.

After you get it flushed out good, you might want to drain the water from the radiator (and engine block if you can get to the drain plugs) to make room for adding half the capacity in straight anti-freeze. You want to use something other than Dexcool and you might want to replace the pressure cap. You should be good to go after doing all that.