Backstory:
I own a 2012 v6 convertible with about 140k miles and installed an aftermarket JVC radio about a year ago.
Originally I lived in Texas in an area where it hardly ever rained, then on one occasion I went to Louisiana to help a friend move where it rained fairly hard. I noticed my climate system was acting up, and when it was on it sounded like sizzling under the glove box when I took a turn or accelerated/decelerated. My buddy assured me it was the rain hitting the exhaust...but I was not convinced, especially after my climate system was acting so weird out of nowhere. All of this happened while the weather was chilly so I never really needed A/C but I did notice on my way home to Texas that it was not working. The weird part was that the blower controls and the temperature controls seemed to work fine (with the exception of a sizzling sound during heavy rain) but the A/C never worked after that point. Again, no big deal since I was mostly using heat or had the windows open anyway, but still something I wanted fixed.

I have recently moved to Florida where it rains constantly...which finally led me to the source of the sizzling which was a clogged up plenum drain (?) that backed up the water through my cabin air filter into my blower (I think).
The DAY that I dumped the drains my A/C was blowing strong on MAX and noticeably cold, and everything seemed right in the world.

A day or two later, she had to go into the shop for a severely deteriorating radiator system that I was not prepared to fix myself and I had the pleasure of renting a Kia Soul for about a week while it was worked on (2/10, might recommend).
When I got my car back, the A/C was back on its bull****; no cold air when on, no cold air or increased blower power when on MAX A/C. The dealership I took it to in Texas ASSURED me that my aftermarket radio controller was not providing power to the A/C clutch and I would need to figure that out on my own, so I have been chasing an electrical issue for the most part. I am coming here now, because I need to try other troubleshooting areas and have no idea where to start. Again, after trying the old faceplate I'm certain that is not the issue. (For the record, the controller is an iDatalink Maestro Rr). I have scoured forums and YouTube videos for remedies because I still believe that the water coming through the blower is related to the A/C not working but have found nothing. If anyone has other ideas to troubleshoot A/C, I'm still quite new to this realm and would appreciate any advice.

Below is a list of things I have already attempted to try to fix this issue:
-Fuses / relays are all good
-Freon is charged
-Aftermarket radio controller still works on the climate system, the old stock radio/climate control face plate was reinstalled with the same result; adjustable temperature and blower levels with no A/C or MAX A/C
-Might be unrelated, but blower and blower motor resistor were recently replaced

Potential notable symptoms:
-Lack of increased blower power in MAX A/C
-Lack of cold air
-Radiator fan does not engage when A/C is powered on

Greatly appreciate any help
-Burz

 

So long story longer, it was the blower motor resistor/the wiring harness. The water dripping in thru the blower must have shorted the blower motor resistor and/or corroded the harness (green buildup..). I replaced both components with a kit from Amazon and everything works like new again. Some help diagnosing this with an OBD2 Scanner and ForScan aided me in solodifying the fact that the issue was in fact with no electrical current reaching this component. Thanks for all the help and support!!!

 

Thanks for posting back with the fix and mystery sound resolved.. Sounds like the sizzle was the water hitting the heat synch?

I have an 08 so it doesn't apply to me but, just wanted to comment on the MAX A/C setting. It does not increase blower output, what it does is override the temp control (so it stays on until you tell it to turn off) and also sets the vents to recirculate so it's always circulating the air within the passenger compartment. The reason it sounds like the blower speed has increased is that there's more resistance in recirculate mode. You can try this yourself by turning on the AC and manually switching to Recirculate. It'll sound the same as MAX A/C and feel like the same volume of air.

 

I'm not sure if it was hitting the heat sink or the blower itself. When I noticed which driving actions caused the sizzling (quick accel/deceleration & full 90-degree turns during heavy rain with the climate system on; pre-drain clog fix), I messed around with some climate settings to see if the sizzling reacted positively or negatively if not at all. What I found was when the blower was in a high setting it got worse, and when I shut the climate system off completely, the sound would fade out. This lead me to believe that water was being introduced directly to the blower fan (especially after finding that clogged drain right next to the firewall AND cabin air filter), but what a strange sound...It really would not surprise me if it was the heat sink.

Also, thanks for the heads up about the MAX A/C setting. I've never noticed that before.