Weird heater issue

[Duckslayer]

I’m new on this forum and I researched my ass off and didn’t find this issue before starting a new thread, sorry if it is out there already. I drive a 2006 Sierra vortec max 140,000 miles. Recently when I first start the truck and let it warm up to operating temp with the heater on and the temp settings cranked all the way up it will blow cold air until I turn the heater off and turn it back on than it starts blowing hot instantly.its hot enough to defrost the windshield but still freeze my nuts off  Has anyone experienced this before? 

[txab]

Sounds like actuator issues. You've got 4 of them. 

 

*Thanks Swathdiver*

Quote

 

The Driver's Side Air Temperature Valve Actuator is under the dash on the passenger side. 

The same actuator for the passenger side is to the right of the center vents. 

The Mode Valve Actuator is just to the left of the center vents (commonly called blend door).

The Air Inlet Valve Actuator is behind the glove box.

 

Air Inlet Valve Actuator 89018365 15-72971 Dorman - 604-106 Mode Valve Actuator 89018374 15-73952 Dorman - 604-112 Temperature Valve Actuator - Driver's Side 89018375 15-72972 Dorman - 604-111 Temperature Valve Actuator - Passenger Side 89018375 15-72972 Dorman - 604-111

 

No heat from any vent until you cycle off/on? Does the passenger side get warm, but drivers side stays cold? If so, the culprit actuator is on the passenger side above the trans tunnel. Fairly easy to replace. Several threads cover it.  Also many Youtube videos as well

[Duckslayer]

Well ironically enough it just started working all the time.but it was super weird everything it blew the same cold temp out of all vents even when the truck was at operating temp I’d get in cycle the heater control off then on and instant heat.