AC Fan Speed Issues After Audio Install

Misnomer

NOTE: I tried searching the forum for this issue, a couple of different ways -- including reading the Problems and Fixes After Car Audio Installs sticky -- but I didn't find it. I hope there isn't a recent related thread that I somehow missed.

Last month I had a Kenwood eXcelon DDX6902S professionally installed, and everything is awesome except that I swear the fan doesn't blow as hard as it used to. [Insert BJ joke here.] Air does come out, but I have to turn it up past the midpoint to get the same amount I used to get well below that. I've owned my Z for 2.5 years and have never had to turn the fan up as far as the midpoint before. Only the dashboard vents are affected: the door vents are unchanged, which means I have to deal with a freaking hurricane coming out of the door vents in order to get any significant blowing out of the dash vents.

When I took it back to the installer he said the temperature controls are just simple connections, if they hadn't been reconnected right the A/C wouldn't be working at all, and that there's no way anything could be partially blocking the dash vents (which was my only guess). He also didn't agree that different amounts of air are coming out of the door vents vs the dash vents.

I have no way to prove that the fan was different before the install, and everything else is great, so I shrugged and didn't press the issue. I mean, it's not like the A/C doesn't work. But every time I use it, I notice the thing with the fan...I'm starting to wonder if I'm just totally losing my mind.

Anyone ever have this issue after an audio install? Any suggestions?