2008 Max - AC Automatically Turns On / AC Controls Wont Do Anything
 

Hello fellow Maxima owners!
I'm having this weird problem where every time i turn the car on, the AC and Blower automatically turn on. The AC control unit does nothing (it does light up, with the AC lit amber), when i press the button to shut the AC unit off, it isn't responsive. The AC display is also on, its set to 75 and cannot be adjusted.

A little context before these issues started, my car was parked outside my house and this thug broke into my max to steal the radio. Yes, you heard right, in this day and age, in 2019, people still steal radios in LA. Anyways, he cut many of the wire harnesses connected to the radio, AC Unified Module (white box) and information displays. I was able to get a hold of all the connectors and stripped / soldered and shrink wrapped each one.

Once i received the new radio assembly, i connected everything back together - the following restored:
- I was able to turn my car on (car wasn't turning on without the AC Unified module)
- The cluster began working again (cluster needles for RPM, Fuel, Temperature and RPM did not move when Car was switched to on)
- The Radio turned on and i was able to listen to music again (yay)
- The Radio Display Unit also works now
- The AC Display turns on

So, mostly everything is working back to normal, just that one annoying issue where the AC will not turn off when the car is on. The Blower and AC will automatically turn on when the ignition switch is turned.

Things that I've checked so far.
- Fuses, all of the fuses look okay, nothing looks to be blown.
- Disconnected the battery for 30 minutes and turned it back on. Same issue.
- Replaced the AC Unified box (no pennies or other currency shorting the box), same issue, AC wont turn off.
- Inspected the Air Blower Resistor (located underneath the dash), near one of the teeth, the plastic looked a little burned, when i took the sleeve off, the board looked okay, would this be needed a replacement?

At any rate, thank you guys in advance, hopefully one of you has had this issue and can help me narrow down this issue. I'm currently at a loss.
P.S - some of you here in LA might say, it's HOT, why not just leave it on all the time? i would, but it seems like the idle pulley is going bad because once the car comes under load (from the compressor clutch engaging), it squeals and will take like 5 seconds to go away.. highly annoying. I've already replaced both belts. The issue went away for a couple of days, but it seemed to have returned.

Anyways, thanks for taking the time to read through all this. I love the max, just want to get these small issues taken care of and it'll be ready for another 10 years of ownership lol..

Anyone?

The same thing happened on my 09 Pathfinder. The blower resistor was the fix.

Of course I did not have all the repair involved that you did, but the symptom was the same. Replacing the blower resistor fixed it.

Thanks for the help, i'll head out to my local autozone and grab one this afternoon and will report back. Thanks again for your help.

Doesn't look like replacing the blower resistor fixed it. I replaced it and turned the car on. The AC kicked on automatically and the controls weren't doing anything. The AC control panel was lit (amber lights), but they weren't responsive. Any other ideas?

Download the FSM and go through the AC troubleshooting pages step by step.