Chevrolet: 1995 Blazer heater stops blowing air, coolent, rad cap

Question
I have just bought a 95 Blazer. It will blow warm air for maybe 10 minutes and then it quits. You can put your hand to the vent and nothing. I have to shut the heater off for a while and try it again. Same thing happens. warm for only awhile and that's it.. Any suggestions would be great.. thanks

Answer
Jacob;
HI- I would flush the cooling system if it has not been done in the past year, than check the heater hoses when the motor  is warm not hot if both hoses are the same temp thats ok but if not than the cont. valve is bad.  and check that the coolent is full and the rad cap is ok. the inside switch could be bad too so there is a few things to check out you can get a rad. pressure test taken  to check for any leaks.