heating issue

What is your question?

Can I ask a repair question? I have a `1997 Toyota Tacoma. I changed the water pump, thermostat, & the radiator is less then 2 years old. The heat stopped working, blows cool air. I flushed the system with cleaner it heated for 30 min & quit again. There is no smoke or water coming out of the exhaust. I see there are 2 fuses how do you know if they are good or bad. I have asked 3 local Toyota mechanics & they never heard of this issue.