AC question

That's how it's supposed to work. Nothing is wrong.

If I understand correctly, the AC will kick on when you putg teh controls to defrost. This is normal. Don't ask me why. I just read it in my manual.

Your AC is supposed to run in the defrost mode, and the setting with both the front vent and floor vents on.

The only modes which the AC does NOT run are: OFF, VENT, and FEET ONLY.

Do you people ever read your owner's manuals?

You've already had the nitty gritty replies...... now the "why?"....... any time that air is directed towards glass, the AC compressor is cycled to reduce the humidity of the air (cold air can't support as much water vapour as warm air) in order to minimize fogging. Through the marvels of modern engineering, the air can be passed through the heater core after it is passed through the evaporater core.

As for the owners manual...... there is a wealth of information contained in it's pages - some of it may be pleasantly surprising. I find it amazing that people will invest thousands of dollars into a machine that can kill them without any regard for operating and safety features, etc.....

As for your last statement, I'm reminded of an AC repair several years ago. I remarked that the customer had a particularly nasty oil leak and he should have it addressed. A call came a few days later..... "Ever since you fixed my AC, I've been using a lot of oil.....". Go figure.....

I appreciate all the information and yes the criticism, I have never noticed the cycling of the compressor in the other settings except AC.

It is my wife's truck and she is the one that noticed the compressor running at the other settings. I guess she never had the temp control set on cold for defrost.

I do read the owners Manuel, as well as the shop manual I purchased. I don't claim to be a mechanic but this was the first time I have had the truck to a dealer. I really don't care for dealers much.

I have done rotors and brakes, fuel and air filters, flushed the coolant and regularly change the oil and filter using Mobil 1.

Hell, cant' always be right and I was brought up to believe there is no such thing as a stupid question.

Again, thanks for the responses and I am glad there is this forum to throw out my questions.

It doesn't have to be on "cold for defrost" -- it only has to be in any of those "heat" modes which include more than just the foot vents. The temp control can be on full high, and the AC will still be enabled in those modes.

Me neither. Which is why I read the manual!

You're right, in principle, but you would be amazed at some of the questions people ask in newsgroups.

You noticed that all the answers gave you information, though, didn't they? People were helpful, even if they questioned your reading of the manual, weren't they?

Enjoy!