2005 Pacifica

This is weird to me. Back in september we were on vacation back east and the car started randomly throwing a P0072 Ambient Air Temp Circuit Open code, setting the CEL, and AC wouldn't function. Continued to randomly trip again after resetting, until it started hard setting at key on.

Replaced sensor, no change.

Anticipating the typical wire exposure failure, I picked up a very clean and not even faded harness cut from a salvage yard. Checked it for solid continuity across both wires and no problems noted. Spliced it in today, solder and heat shrink, then wrapped with harness tape (non adhesive), put back in loom, etc.

NOW.........according to my scanner, the PCM is reading accurate ambient air temp (62°), voltage reflects corresponding air temp (2.33v by memory), and will spike to 4.94 if I unplug the harness. BUT. HVAC display still shows -40 and AC doesn't kick on. I only idled in the garage for a couple of minutes. Is there a delay before the temp reading on the HVAC display starts to update? Vehicle did NOT trip the P0072 at key on or while idling. Key On Engine Off across the harness connector I get 4.94 Volts as I should. Resistance across sensor changes with temp changes correspondingly.

Even more strange, I disassembled the old harness and found nothing awry other than the wire covering being faded. Stripped the wire out of the covering, and every strand was intact, and I cut it off approx 10" back from the connector, just before it enters the main harness bundle.