BILs car, 3.0 V6. No AC. Jumpered the relay and the compressor came on, and it swallowed a can of R134a, showing 20 pounds on the low side at 75'F ambient. The rad fans came on as the can was consumed, and the vent temps dropped nicely to the mid-40s. It'll go below 32 when I rev to 2500 RPM but I don't want to freeze things up.
I am familiar with the evaporator temp sensors going wonky, as per this thread.
Probed mine for ohms, shows 14 mega-ohms (and variable), a plausible but warm-ish 120'F per that chart. Still, it could be that temp in the hot sun near the firewall, maybe? I did try splicing in some resistors, in my case, 33 MOhms worth, without improvement. In fact it seems to have panicked and chosen defroster during some of my experiments.
Also, the underhood relay coil contacts confuse me. One shows ~3 volts, and the other a bunch, but not infinite, ohms to ground.