2000 V70 SE 130k miles...

For past few months, a/c would work intermittently, nice and cold but then would blow hot. Tolerable until now, with the approaching warmer weather.

Took the car to Volvo agency three weeks ago, they said it required evacuation, vacuum and recharge ($250).

It didn't fix the problem and after they finally spent time / troubleshoot today and experience the cold then hot, they say it needs a new compressor ($1500).

My question is: can it really be the compressor if it blows cold part of the time? As a mechanical device, the compressor either works, or it doesn't? I thought it more likely to be a switch or sensor; but all the service writer could say is that the entire compressor had to be replaced and it could be an internal electrical issue.

Thoughts? And could this be a DIY job?

Thanks, Robert