No heat at idle?

Hello, I've read a lot on the forum but this is my first post. I've normally been able to find great info on everything I've needed but I've come up dry on this one.

I have an 07 prius with 105k miles. It had no warning lights on and drives great with 1 exception. The heat gets cold at idle, it works great as soon as i drive or if the ICE starts to charge the battery. I believe the problem was the ICE not coming on to heat it back up, it would only come on if the battery drops not if the air temp drops. Then my mechanic replaced the pump on the coolant heat storage tank and it made no difference so he put the old one back on. However since then the ICE will occasionally kick on for heat even if the battery is charged (like it should be) but not frequently enough and sometimes not at all.

Any help would be greatly appreciated, I have searched everywhere abs my mechanic doesn't have any ideas. I'm hoping to avoid the dealer.

Thanks for any help, ideas, or suggestions.

 

1 correction, the ICE is not kicking on at all except to charge battery. The time it kicked on after the pump replacement must have been a fluke or part of warm up.

Thank you will check that pump right now.

It is on max heat, I've tried all fan settings, recirculation, ac, and auto.

 

You are awesome, the connector was not seated properly. Pushed it in and now it works properly.

Thank you so much!The connector on the heater core pump that is.