Trying t solve why AC controls don’t control the AC. All new OEM AC system (compressor/condenser), then switched out control panel and now swapped the AMP module too. Dealer said couldn’t connect to original AMP. All I get is fan speeds and ac on or off. When on it blows max cold regardless of temp set. When off won’t heat air either. Can change fresh/recirc. but won’t change flow modes.
Anyone know if the AMP has to be factory reset or what the heck else this could be?
Thanks in advance!
2011 G37 6M Conv.

 

All of these point to possible issues with the blend doors (temp) and the mode door.

Simple test, with the key ON (not ACC)/ engine OFF, place your ear as close as you can to the HVAC box as you can (this is located under the dash/ behind the center console). Turn the temperature dial(s) from 60 to 90- do you hear a little "buzzing" sound? It will be faint and will last only a few seconds. You might have to cycle the dial a few times. Repeat this test but with the MODE button. Again, you should hear a little buzzing sound.

What I suspect is that your blend/ mode doors are not moving as commanded by the controller. Though rare, there have been reports in the past of these motors going bad and/or the actual doors getting "stuck" for whatever reasons. You might have to get under there and inspect each motor/ wiring connection.

If you have not already, download a copy of the HAC (Heating & Air Conditioning System) section of the Factory Manual from here. This will have a more detailed explanation of how the system operates and have further diagnostic protocols. There is no "master reset" for the system, however, there is a very detailed "self-diagnostic" function built-in that will point you in the right direction.

***Friendly reminder, as you have a 'Vert and those cars get real fussy with battery voltages, do not leave the key ON longer than necessary. If you have a battery charger/ maintainer, I would connect that while you diagnose the issue.

 

No whirring sounds at all. I think the ac is in failsafe mode.
Ran the self test from the manual (Thanks Again). Received some error codes and using the manual to try to move forward but I am getting over my skis. This is my 4th shot at replying, they keep disappearing.
IndyAndy

 

What are the diagnostic error codes that are being detected?

 

Thanks for your interest ILM.

Sensor & Door Motor Circuits Test 2 : 25,26,-26,27,-27
Mode Door & Intake Door Positions Test 3. : 31,32,37,38,39
Operation of each Door Motor Test 4. : 41&42 then no more
Can skip to Test 5 Temps.

The HAC manual is awesome, I am learning a lot, but the sublinks aren’t going anywhere.
My wife wants me to sell it rather than spend another $2k on the AC. I’m not in favor but I think I’m just wasting your & my time trying to solve this with no experience.

Andy

 

I will not comment on the marital aspect... If there is nothing else wrong with the car except for AC then I would get it fixed. Even though it is a 'Vert you will still need a working AC living in Florida. But, in the end you have to decide what you/ you skills/ and your wallet can afford. As for time, if it gets the issue resolved than to me it is time well spent.

That said, the odds of one blend door motor going bad is highly rare, the odds of ALL door motors going bad at once are incalculably astronomical. It just doesn't happen. Also, the odds of both amps having the same bad behaviour is virtually impossible. I highly suspect there is a wiring issue somewhere causing this problem.

There are only 3 possible culprits for ALL of those doors to go unresponsive: power, ground, and signal. How skilled are you with a multimeter? If it were me, I would check that there is power (12V/ pin 70) and a good ground (pins 55 & 71) coming from the amp. If good, then from there you would test for P&G at each door motor connector and/ or use a jumper wire to try manually moving each door.

Did this issue just pop up "out of the blue?" Was any work done to the car that could have contributed to this mystery?

 

Trouble started when AC went from cooling to blowing but not cooling intermittently.
1st shop thought it was leaking refrig. And needed new system. Second shop had a different failure but same cure. Something told me they were missing the call so 3rd shop, a real ac specialist, ended up putting in new system and lots of troubleshooting including new control panel at no charge but ended up throwing hands up saying the system is just not communicating.
then to the dealer who suggested the new AC AMP.

it is a good car and drivable wAC in failsafe. Just no heat or windshield defroster. (Rear defrost works).

I agree with your diagnosis.

I had an automatic sedan for years with no troubles. Then moving to FL and not commuting in ATL traffic I flipped to the 6MT Vert.
both great cars!

So my quest will be to get & learn multimeter or find someone around here who knows.
I wouldn’t be this far without you .
Thank You!

Andy