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I have been bringing my 2005 civic coup back to life after it sat for about 5 years.
Already replaced the fuel pump, brakes, tires, wipers and more.

It runs like a top with a few codes that are unrelated to AC which I am addressing separately (P0113 and P0497 in case they could somehow be involved).

Not surprisingly, the system blew hot air only so I started tackling that issue...
Symptom: When the AC is turned on high and set to recirculate cold air does not blow.
I can see that the AC pump clutch is not engaging.

Already completed:

• Checked all fuses under the hood, behind the glove box and under the steering column with a multimeter. All good.
• Tested the relay by swapping it with the horn relay. Horn works with both, so it's good.
• Tested the AC clutch by hot-wiring the AC relay pins in the fuse box and the clutch engaged, so there isn't an issue with the clutch
• Refilled with refrigerant while hot-wiring the clutch to cycle the coolant (note that the AC does start working when this is done, so the pump works as well!)

After all of that, the clutch doesn't come on unless it is hot-wired. The relay must not be getting a signal to close the circuit.
I suspect that there is an issue with the AC pressure sensor. I did pull the wire off and used a bit of copper wire to close the circuit but that had no effect. Not sure if that's the right way to bypass it.

Any thoughts?

PS I don't have a good service manual for the v7 civic, if someone knows where one is, I would appreciate your help there. There is a download pdf link on the forum, but that looks like an ad to me and it links to an executable rather than a pdf so I'm very hesitant to click it.