Sometimes AC sometimes not

My 2005 Legacy GT(151k) developed an AC issue. Sometimes it simply does not work when you start the car. Other times perfectly. I typically shut the climate control off(automatic) as I cannot stand hot air blowing on me. I have found it does kick on sometimes latter in drive. Or even just works fine.

I got lucky on my Acura MDX 07 with a similar issue but was able to google a known issue with AC clutch relay. It was fixed for $6 relay from Honda dealer. This part seems more expensive on the Subaru (OEM) at $40 for blind guess.

Any steps for electrical diagnosis or subie tips? I am convinced it is not refrigerant related(over my head) since the AC works the same as brand new when working.

Yeah. Sounds like it’s possibly the clutch itself. It will work occasionally when too thin, especially when cold, but eventually not at all. If the AC is on and the clutch is not engaged, it is possible to poke it assertively with something – the business end of a ratchet or a hammer – and get it to engage. If that works, you’ll know it’s the clutch. The problem is the so-called “air gap” of a too-thin clutch.

Had the same problem with my 04. It was the ac clutch. I was able to rent a clutch removal tool from the auto part store for free. Took it off and removed the two spacer washers that were in there. It is working like a charm now. I am sure it will eventually wear down again, but this bought me some time, for free…