Title says most of it. I noticed the windows fogging up during a drive the other day, so I turn on the automatic defrost, which activates the air conditioning, but nothing happened. The fan was blowing hard into the front window, but the air was noticeably damp. After about 10 minutes, the compressor suddenly decided to engage and the window was clear in 30 seconds. Later that day, the same thing again.

Now it appears the compressor doesn't want to come on at all. I sit at idle and toggle the air conditioning on and off and never hear it engage.

The question is what can I DIY in this situation? Could be as simple as a loss of R134, although when it did engage, it seemed to work wonderfully. Also, during the summer, the air conditioned air was absolutely ice cold, indicating no slow loss of refrigerant.

What else can I do to troubleshoot before I take it someone and undoubtedly spend $1000+?