Two 850's, two different a/c problems. First one the compression clutch won't engage. It's fine when I connect it directly to the battery. I don't seem to be getting any voltage at the low pressure switch. The 1,2 & 3 settings on the fan switch are out, but 4 works. Fuses 5 and 31 are fine. I'm assuming my fan resistor is bad, although I just replaced it a few months ago. If the resistor goes out, does the prevent the clutch from engaging?

Second, the other 850, you guessed it, has a compressor that stays on unless I disconnect the low pressure switch. I put another low pressure switch in, but it made no difference. Any thoughts?