My mechanice can't figure out what is wrong with the AC on my 2008 honda accord. Sometimes it works, mostly it blows regular temp air.

If the temp. outside is above 85, the a/c only works for a minute or two.  He
says it isn't the relays,or compressor clutch, and he just charged me $600 to
replace the  control panel.  I just drove the car, and the a/c stopped working
after 5 minutes.  I switched the a/c off, then back on, and the air was cool for a
few more minutes, then regular air.