2000 Volvo S70 A/C Troubles

[Eddienorgard]

hello all!

I've been experiencing some A/C issues with this car for a couple of years now and I decided that this would be the year I actually fix it once and for all. Here is everything I'm noticing:
1) at idle the compressor engages when you turn the A/C on but disengages about 10 seconds later. It will then turn on again another 10 seconds after that.
2) when driving at high speeds on a hot day, the A/C stays on and is cold.
3) breaking and accelerating greatly affects the compressor engaging.
4) on a cooler day (70F or cooler) the A/C will engage properly and blow cold air.

What the HECK is going on?! I want my A/C back! It sure gets hot and wide open windows are simply not enough for me! Any suggestions?! Thanks in advance!!