I am looking to rig up the heater to work on my truck. Currently the heater and AC work very poorly and obviously the Book symbol is on. The air is luke warm in the summer and luke warm in the winter. I suspect a blend motor may be stuck in between hot and cold. I also have a problem with condensation and frost build up on the inside so I think it is also stuck on recirculate. What I would like to do is permanently set it on Heat, Fresh Air, Defrost. The fan control works so I should be able to control the temp that way. Help