I have a 1995 Ranger XLT with a 3.0 the truck blows hot heat and cold air, but the gauge that controls the heat/cool amount doesn't work. I will have the truck on defrost and no matter it is on medium heat or all the way on cold is blows hottest air possible. I heard this may be due to a vacuum leak does anyone know what may be causing this? Also, AC only works on MAX AC, when turned to regular AC it blows hot air.

Any replies are appreciated
Thanks, Chanse