Winters coming and where I live its going to feel like -20 this weekend. my heat has been a luke warm temperature the trucks heating up fine I just put a Thermostat in it as well as did a coolant flush hoping that would fix the problem but still nothing. The actuator is spinning and i can tell a difference between the hot and cold so I know it's working. What else could be the problem? Any help is appreciated

 

Are both heater hoses hot? The heater core could be plugged or the blend door broken.

 

Forgot to mention I flushed the heater core couple weeks back too. Say the blend door is broke how would I check to make sure and how big of a job would that be?

 

I flushed my core too but heat was not hot for years. Finally broke down and got a new one. TONS of heat! It's time to just do it.

 

DITTO!
Core replacement sure is a PITA!! Have at least one bungee cord handy to keep the dash stable after pulling it away. If your dash is all cracked up, you'll be making more slivers. If it's not cracked, it will be before you finish. Core mfr. might recommend filling system with distilled water. I'd do so for sure. Probably ok to flush system with tap water but definitely refill with distilled water. Here in GA it's available at Dollar General for a buck a gallon. Their antifreeze (Peak) is a cpl bucks less than at parts stores, where I was told to use the universal blend. BTW: a/c lines DID have to be purged and disconnected before starting. PLEASE do not purge into open air but into a recovery tank. Refill from same.
Best of luck to ya.

 

Get your head down to the blower assy., fan speed on low, turn temp\heat control **** from cold to hot and back again, kinda slow. You should be able to hear the blend door's actuator run. If not, probably a bad connection down there. I disconnected and reconnected mine, tapped hard on its housing and it started working. I've heard other owners say the blend door can break away from its hinge pin, for lack of a better term. If that's the case, replace it. I have no idea how. Repair manual might explain how, maybe just in the section for removing the blower.

 

I'd say he's ruled out a bad connection.

If the door pivot has failed it hopefully occurred at the coupler between actuator and door "hinge". Heater Treater fixes this. Lots of good vids on YT. The first ~2 minutes here show the problem (not my vid)