Something’s going on here. 1500 is to high. I would suspect maybe something going on like a duff sensor (coolant temp sensor comes to mind…just as a possible one….)
Can you get a scan tool for the system and monitor the readings for a short while? I’m interested in seeing if the engine temp is doing it’s thing correctly.
As a rule, you turn on the A/C at idle. The system will automatically bump your idle up so not to stall or bog the engine down. I think there’s a couple of things in play here. What year are we talking about?
S-