Cant find a vacuum leak. Heat n AC work. But the "blend" indicator just blinks. Befor it would only switch between df dash and floor, wouldn't.
My '04 did the same thing after I replaced the battery. Thinking something was up, I googled it and on page two I found this gem:
Turn the climate control and the radio off.
pull the fuse under the hood marked hvac/ecas 10 amp in the right side
Leave the fuse out for about a minute.
reinstall the fuse.
******do not touch the c.c. switch when you restart the truck******
restart the truck, the c.c. will automatically reset to 74* and start cycling.
it will take about 1 min for the c.c. to reset itself, you should hear it running through the cycles.
there has been one or two times I've had to go through this procedure a couple of times for it to reset.
Worked.