I have a 08 F350 diesel with dual zone climate control. In the winter the driver side heat seems to blow only cold air after the cab has reached the set temp. It will stay blowing cold air unless I bump it up 2-3 degrees, then it will blow heat again HOT until it reaches set temp ushally a few minutes, then it will stay blowing cold. The passanger side has no issues. I have read about electric actuators going bad, but would it still blow heat sometimes if it was bad? Is there a temp sensor that goes bad? Help winter is almost over and truck will be off warranty by next winter.
It still seems to blow cold air after a bit. I found if I leave the temp cranked and the fan on low I can keep constant heat. But if I leave it at 72 and have the fan on high or medium it will blow cold still.
There are known issues with blend door actuators in trucks built before 11/06/08. Monitoring their operation with the proper scan tool can show if they are bad, which obviously requires replacement of one or both of the actuators.
The passenger side is easy to get to, the driver's side is around 5 hours labor for an experienced tech and requires removal of the evaporator core housing, recharging A/C system, etc.
I had the same issue, except that it was on the passenger side. I took it in and they told me the longest story in the world, meaning it was normal to have to continualy adjust... it didnt make sense. Now my heat is out all together...