The driver's side air conditioning in our Suburban switches to hot air after 10-15 minutes. The only way to start the cool air again is to turn off and restart the engine. Any ideas as to what's happening and how to fix it? I'd like to fix it myself if possible. TIA

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"You never want a serious crisis to go to waste. And what I mean by that is an opportunity to do things you think you could not do before.

- Rahm Emanuel, White House Chief of Staff, November 2008