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The does the light illuminate in the A/C switch when you turn the blower and the AC switch on? Does the magnetic relay click at the same time? There have been issues with the AC magnetic clutch relay. Swap magnetic clutch relay with the horn relay to see if the A/C compressor kicks in. Let me know what you find.
The magnetic clutch relay is next to the headlight relay in the fuse box under the hood it is labeled: M/G CLT
It's hard to say why they don't, they've always called it a magnetic clutch relay but at least he got it fixed and you can use your air conditioning.