AC/HEATER problems

[J-Ro]

Hey everyone this is my 1st time postingsomething on here and I was wondering if I could get some advice on whats wrong with my 04 Rx-8

Ok my issue is that whenever it is hot out I turn on my AC and it blows hot air and when its cold out I turn on my heater and it blows cold air. Can someone please help me out with this?

 

[Shadow102]

A couple of more questions. Does it blow warm air all the time or when the ac is on does it blow super hot air and when the heat is on does it blow freezing cold air?

 

[J-Ro]

It depends on the weather outside. If it is superhot 80+ out then it will be hot air but lets say its 60 or below it will blow cold air.

 

[coyfish]

Or is the temp the same but you just think its cold / hot because of the ambient temp . . .

 

[solidtrance]

You are not crazy. This was happening to my car this spring and summer. It turns out that the heater control unit in the RX8 have a flaw from the factory. The "hot/cold" dial is not properly soldered to the circuit board in the heater control unit. There is a way to test this:

No heat and only cooling, or only heat and no cooling, or erratic temperature control?

The temperature control knob seems to have quite a bit of issues for early RX8 owners where the system will cool only, and not provide heat despite the position of the control knob. This can also work in the opposite way, only heating and no cooling. After living with it for a season, I finally pulled the heater control unit out and repaired the circuit board. It was simple to repair and because I was going to have to pull the unit out anyway to replace it, it was not much extra work. The replacement unit (part FE01-61-190) retails for $350, some vendors on this site sell it for $240ish, and I hear there are some that sell used parts for $125ish. It is definitely covered under warranty for those lucky enough to be under warranty.
If you do not have heat, or only have heat, IMHO it is most likey the AC/heater control unit. This is the part which has the AC/heat control buttons and knobs.

Easy Diagnosis:
The easiest way to verify this is to turn on the radio, press and hold the power on/off button and press and hold the scan-up button for a second (full second). The word "A/C TEMP" should appear on the left of the display and a number from 0 to 16 on the right. I suspect yours will have the number 0 (or 16 if heating only problem) displayed no matter where you turn the temperature control knob. If this is the case you could turn the temp. knob to full heat and see if it goes to 16 after pushing down or to the right on the knob.
In a working system, the number moves evenly in increments of 1, from 0 to 16 as you turn the temperature knob.

Easy Fix:
I was able to take mine out and solder 3 loose connections to fix it.

all this is strait from the DIY on that other RX8 Forum that will show you how to fix the problem


I did this myself a few months ago and it worked like a charm. I was amazed how bad the factory soldering was. I don't even want to contemplate how much a stealership would charge to do this.. I took my time and I think it took less than 3 hours. You just need to fond someone with a soldering iron and some solder.

Sorry for all the appearance of this post, I took it from some posts I made on my local RX8 forum (here in Chicago). One of the members was having the same problem. I have been through this whole process myself, from uncontrollable temp in the car all the way to a completely fixed heating and cooling system in the car, and it was not too hard to fix. I did it five or six months ago and the problem is totally solved. If you want a direct link PM me, as the mods here don't want links to another site.

Hope this helps!

Caleb

 

[abass23]

04 Mazda RX-8 AC Issues

On my 04 RX-8 the AC sometimes blows ice cold but not for very long, it then turns to hot air, on a warm or hot summer day. In the cold weather it blows cold air out. Its a very frustrating problem. Can someone please help? I am hearing a variety of different fixes. I am located in the Chicago land area as well if anyone can offer some advice, or I would be willing to have you look at my car. Thanks.