DerekS

I'm getting fairly weak AC - the air is cool, but not cold. In 90+ weather, it doesn't get the car cool enough to matter.

Possibly related, it seems to make a lot of weird sounds in the cabin when it's on. Hissing noises, etc.

I'm guessing at minimum it needs a recharge, and at worst I've got a leak in the system somewhere.

Any DIY troubleshooting suggestions? (My dealer can't see me for 3 weeks)

Homeles

Find a new dealer. Seriously, unless you have access to the needed equipment, leave it for the pros.

kyrocks

Get a new dealer.
I had a solenoid fail in my TTS with same symptoms as you.

DerekS

Well all the dealers in the Bay Area seem to be booked.

Pmorritt

Under warranty or not, more than likely just a Change Over Valve for the AC. ( also called a solenoid) There is a bank of them suckers for various stuff. Not expensive and just a minor known issue. There were a bunch of failed ones from jobber suppliers. Had mine fail after 6 months. Almost 3 years later all good.

DerekS

I already had one COV fail, it was the sound symposer.

StormRune

Just to make sure: Are you aware of the AC settings available on the PCM stalk controls? It's under the Vehicle Settings menu.

If you have it set to Soft you will experience reduced cooling performance. You can also select whether or not to use the Extended Ventilation Panel. I figure if it is set to Soft and you're not familiar with those tucked-away controls that may explain the problem. If you set it to Strong you should get very good performance (too much for me!). I'm also a big "fan" of enabling the ventilation panel since it creates a slower moving mass of air and distributes the cooling more evenly across the upper body and head.

DerekS

I didn't think about that StormRune, I'll see if it makes a difference.

I'm pretty sure the issue isn't the blower speed, it's the temperature. I'm guessing I took a rock to the condenser and made a hole, or something. Will report back in a million weeks when I get it looked at.