Auto climate control question.

JimsSpeed3

Member
:
2007 Mazda3 s Sport Hatchback
I did a search and found one other post asking this question so I'm going to ask it again. Why does the AC come on when I use the auto mode? I even turned up my air temp setting to 75* when my outside air thermometer said it was 55* this morning and the AC light never went off. The air being supplied into the cabin felt like it was warming up so now I'm wondering if the air is being dehumidified, that's why the AC is on. Although, I don't live in a humid area so I can't figure it out.
Thanks, Jim
 
that's exactly it, the auto climate control is going to take care of any humidity first, then temperature. when the compressor is running it is going to remove moisture by way of evaporator, then it's going to create the temperature differences by way of blend door.

so it's at least good to know that your system is working fine. when i had my old 3 the dealer told me it was a good idea to run the auto climate every once in a while to keep components lubricated and whatnot. personally i prefer windows down and A/C off, but it's always good to use things every once in a while so they don't sieze up from non use
 
that's exactly it, the auto climate control is going to take care of any humidity first, then temperature. when the compressor is running it is going to remove moisture by way of evaporator, then it's going to create the temperature differences by way of blend door.

so it's at least good to know that your system is working fine. when i had my old 3 the dealer told me it was a good idea to run the auto climate every once in a while to keep components lubricated and whatnot. personally i prefer windows down and A/C off, but it's always good to use things every once in a while so they don't sieze up from non use

Thanks for the response! I did find some more info. the more I dug. I guess the AC light stays on so the AC can be engaged if needed but it doesn't mean that the compressor is actually running. I'm with you though, I prefer the windows down and only use the AC when it's above 90* or so. Just trying to figure out the new car. A lot of the stuff is the same as my old 07 3 Hatchback I traded in for my MS3, just a new few toys. Oh, and the power difference is AMAZING!
Jim
 
that's exactly it, the auto climate control is going to take care of any humidity first, then temperature. when the compressor is running it is going to remove moisture by way of evaporator, then it's going to create the temperature differences by way of blend door.

so it's at least good to know that your system is working fine. when i had my old 3 the dealer told me it was a good idea to run the auto climate every once in a while to keep components lubricated and whatnot. personally i prefer windows down and A/C off, but it's always good to use things every once in a while so they don't sieze up from non use

heh i dont use ac because after 5 minutes when its on I feel like my head will explode
 
You can turn it off too. If you put it on auto and then hit the A/C button, the A/C will go off but it will still control the fan speed and where the air comes out.
 
You can turn it off too. If you put it on auto and then hit the A/C button, the A/C will go off but it will still control the fan speed and where the air comes out.

The A/C will be on ALL THE TIME if you have it in floor mode or bi-mode I believe, no matter what the A/C light says. I might be wrong about which vent settings but I know 100% there are at least two vent settings where the A/C will come on no matter what you do.
 
Really? I would assume it would be on automatically when on defrost, but off for vent and floor.
 
The A/C will be on ALL THE TIME if you have it in floor mode or bi-mode I believe, no matter what the A/C light says. I might be wrong about which vent settings but I know 100% there are at least two vent settings where the A/C will come on no matter what you do.

Yep, the owners manual says (at least in my 07 3, haven't read the Speed 3 manual completely yet) that when the floor vent is selected, the AC is on to dehumidify the air, never experienced that before in any other car or truck. I would assume the Speed 3 is the same. I reread my manual one day when the car felt like the AC compressor was cycling off and on even though I had the temp on heat and the floors vents were on. Later found it in the owners manual and the AC light wasn't on. So even though the auto climate my be heating the car, the AC may still be on dehumidifing the air.
Jim
 
Last edited:
Back