Ok so i'm driving down a nice smooth paved road and I turn on my hvac to defrost and the compressor kicks in. Upon doing so the car starts vibrating like you were driving down a rippled or washboard road. I turn the defrost off to vent. it goes away. I can switch back and fourth without problem now. Still slightly noisy though. Bearing or clutch problem>?
My first thought is that the compressor could be on its way out. I pray for you that isn't it though, as they are bloody expensive.

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The a/c compressor is dying. If you don't want to fix it, unplug it at the compressor so you can still use your defroster, but no more a/c
"say what you mean and mean what you say"
just rip out all your a/c components. weight reduction=t!ts
People say that what doesn't kill you in this life
will make you stronger. I'm not sure if that is true
or not, but i do know one thing-You have to learn from
it and it has to make you better.......it has to.......