The heater in my '77 D150 works too good. I have the temp switch slid over as far it will go to "cool" but it still roasts me out. It doesn't go all the way over to the "cool", I tried moving it over with a screwdriver, but it acts like its blocked. It will slide over to "warm" just fine, but its hot enough as it is. I don't really want to take the whole dash apart to remove the assembly.