Found this forum hoping I could get an issue figured out on a 2008 Anniversary Edition RX8 that has the heater problem. I have done an amazing amount of research and even replaced the heater/ac controls and the problem still exist. Im lost at this point.
Thanks for any help, greatly appreciated.

 

How about you define what "the heater problem" is to you, so we know we are helping with the right problem. More than 1 possibility here.

 

Very true. Ok here is the whole run down on the issue.
The recirc button does not function the recirc, it stays on fresh air, the rear defrost does not switch on at all, the light for the a/c button does not come on but the a/c does come on.
And I did the power button/ up seek test to show the a/c control numbers and on max hot temp it shows 16 and it will only go down to 13 when its on max cold.
I replaced the controls from Mazda and that did nothing. I tried to reset the a/c controls with the holding down recirc and front defrost and it did nothing.

 

Yeah, you don't have the normal problem that the 8 has, which is a simple broken solder connection between the temp control **** and the board. That normal problem never involves the other functions of the control board, which work normally.

Do you have any other electrical issues with the car at all? Even minor?

 

Yes exactly why I am pulling out my hair. As far as I can tell there is no other issues with any other electronics. The radio works fine, as does the steering wheel controls.
The car had been involved in a front end collision a year or so ago.

 

Was there any change in the problem from before you replaced the controls to after? or was everything exactly the same?

 

Not at all. The problem stayed exactly the same with no change with new unit as it did with the old control unit.

 

that is suggesting there is an issue in the harness to the control unit.

I can't answer this specifically for you since i don't recall seeing another similar issue, but i can help walk you through everything.

 

That would be fantastic! Thank you

 

Looking at a wiring diagram, the air mix actuator (relevant to your difficulty getting the temp control lower) and the airflow mode actuator (relevant to recirc vs outside, and includes part of the defroster function) share one wire. All 4 of each of of their wires come from the AC amplifier, however, both modules share a purple wire with a yellow stripe.

The AC amplifier is separate from the center panel that you replaced. It communicates with the AC amplifier, and is a sibling with the Airflow Mode Actuator, the Air Mix Actuator, and the Air Intake Actuator. All 4 communicate with the AC amplifier, but not with each other. There is also a connection to the evap temp sensor, the ambient temp sensor, the PCM, the blower motor resistor, rear window defroster, and refrigerant pressure switch, but i don't think any of those are relevant here.

All modules and sensors get their power from a main power wire to the AC amplifier, which is then carried to each module from there. They ALL share a common grounding point from the AC amplifier as well, grounding back to the amplifier, which then has a single ground wire to the chassis. The first 3 modules plus both ambient and evap sensors also share a common ground circuit back to a single wire at the amplifier, which then passes through the amplifier to the shared ground for everything listed here.

It makes me wonder if you might have an issue with either the amplifier ground wire or the purple/yellow wire that the mode actuator and mix actuator share, or the ground wire to the amplifier that they share.

 

Ok very cool. I have the the dash apart now to be able to access all the wiring and will check those wires that you mentioned.

 

Alright well I looked over the wiring and nothing looks to be messsed up or bad. All the grounds are clean and connected properly. all the plugs are firmly plugged in and non of the wires look messed up. And no change.

 

O btw I just noticed something. On the discplay above the radio next to the little person that shows the direction of the airflow, to the left of that looks like a fan and a scale, that does not light up at all and doesn't show the fan speed on the display. I don't know if that has an relivances or not

 

The amplifier module has been known to be a problem.......

 

Hmm ok. Well i guess ill see if I can get my hands on one and go from there.