ac

The ac compressor turns off and WOT. If it is stopping and going every so often during normal driving it is most likely the High compression switch. It is mounted on the passanger side firewall. To trouble shoot it real quick jump the connector that plugs into it and see if the ac compressor clutch engages and starts turning. Mine did the same thing and is like a $15 part.
 
But if he is low on freon, the a/c will cycle on/off repeatedly.

If he is low, then he has a leak somewhere. You need to find the leak first, then hopefully the a/c compressor isn't blown.
Scott