So this morning I went over to my friend's house who is a mechanic to see about getting my AC recharged. It didn't really need any, so we left it and I drove home. As soon as I pulled out of his driveway, the voltmeter pegged at 18 and the charge/brake light came on. Then the AC turned off. I turned it back on a few times, but now it doesn't come on at all. The voltmeter still reads 18 as soon as you rev it anywhere above 2000 rpm. Needless to say I have no clue what's going on. We didn't do anything other than hook the gauges up to the compressor. That's all we touched.
Any help would be appreciated!