No heat?

[JeepKj96]

Well. My 02 KJ has no heat. sorry let me restate that. it has heat for 30 seconds when warmed up. I had the heater core flushed and my thermostat is good.i just cannot pinpoint where the problem is. Any suggestions?

 

[jeepguy4276]

Blend door, heater core, or waterpump. I did everything but still no heat. Put the water pump in and it gets so hot now. It's easier than pulling the dash apart. I wish I had started there.