I have found this forum to be extremely helpful and has given me the confidence to change out my suspension from air to coil springs and several lock actuators. Some day soon I hope to tackle the 3 Amigos as well. But for now I'm hopeful that someone can help me solve an annoying squeaky sound that comes when I run the heater on a cold day. The sound is intermittent and only there when 32 degrees or lower; the colder it is outside the louder and more constant the noise. I have pulled the panel under the glove box and looked up but don't know where to start. The heater blows hot air even when squeaking and the ac works fine with no noise ever. I'm thinking that the fan is the only moving part but don't want to mess with the system until I get some feedback as it may be noisy but at least it works. Any help is appreciated.