Tom, Speaking from 66 knowledge, the fan control switch pulls out to get more heat. From what I am reading here, it makes me wonder if that lever is not being moved.

Get under the dash and move the lever to see if it is moving on the heater box. (make sure it is moving)

My truck has very bad air leaks so I removed the fresh air inlet hose, put a piece of sheet metal over the hole on the cab side, and recycle air in the cab.

I have plenty of heat now.

Don't know if this will remedy your problem but it might be worth looking at.


guluk





John