Acura MDX SUV Forums banner

1 - 20 of 43 Posts

·
Registered
Joined
·
1 Posts
Discussion Starter #1
My air conditionar doesn't seem as cold as it I think it should be. Granted, I live in Phoenix where it hit 117 this week but I don't think my MDX cools as well as my other 3 (non Acura) vehicles do. Anyone else whining about this?
 

·
Registered
Joined
·
576 Posts
While not at hot here in L.A., I did have the same problem until I learned how to work the rear air-conditioner. My X cools MUCH faster when I remember to turn on the back air conditioner by pressing the the "rear manual" button, with the rear fan on "high" and the temp on max "cold". I didn't realize the X has two separate air-conditioner compressors and the default when you start the truck is for the rear system to always be off. (also why you will sometimes find two puddles under the X when parked and air-conditioners had been on).
 

·
Registered
Joined
·
476 Posts
HARDROCK said:
While not at hot here in L.A., I did have the same problem until I learned how to work the rear air-conditioner. My X cools MUCH faster when I remember to turn on the back air conditioner by pressing the the "rear manual" button, with the rear fan on "high" and the temp on max "cold". I didn't realize the X has two separate air-conditioner compressors and the default when you start the truck is for the rear system to always be off. (also why you will sometimes find two puddles under the X when parked and air-conditioners had been on).

The MDX does NOT have two A/C compressors. The rear heater-A/C is comprised of the following components:
1. Rear A/C line;
2. Rear blower motor;
3. Rear heater-A/C unit & components;
4. Rear heater core;
5. Rear heater-A/C control unit
6. Control motor;
7. Rear air mix control motor and mode motor;
8. Rear power transistor; Rear blower motor relay.

In essence, it is another little heater core and A/C evaporator that is simply part of the main A/C and heater.

I have found that one thing that makes it appear that the air coming out of the front vents is not as cold as it should be is when getting into the car after it has BAKED in the hot sun. The vent ducting and other components are probably getting close to 150 degrees and as such, it takes a lot of time to cool down that mass. I think one thing people can do is use those windshield reflectors to keep the sun from glaring down on the dash. And of course as pointed out in the owner's manual, open the windows to exhaust the hot air for a few moments. That may help. The reason you find two "puddles" is that there are two evaporators.

As for directing some of the coolant to the rear A/C unit, I don't see how that would help as the A/C system has a finite cooling capacity.
 

·
Registered
Joined
·
10,544 Posts
Hmmm, A minute after I turn my AC on, everyone is freezing... I almost works too good.
 

·
Registered
Joined
·
3,761 Posts
Immediate ice cubes in ours. Even when sitting outside in the occassional 100F we get here, it's blowing super-cold (front and back, full auto mode) within a few minutes...which is enough time for the ducts to cool, as norcalchuck mentioned.
 

·
Registered
Joined
·
576 Posts
I guess I've never be a "Super Senior Member" giving such wrong information as I did...

Separate or not, TRY turning on the rear second half of the one and only same overall air conditioner system and see it it helps your problem.
 

·
Registered
Joined
·
78 Posts
I have no problem with the AC. However, I do have
some issue about the control. I would like to use
the full auto to keep the temperature. But when
the temperature reach to the setting level, it automatively
set the recycle back to use the outside air. When outside
temperature reach 100s, I think it is waste to use
outside and I dn't want to turn on the AC always On
by turn off the full auto. Does anyone know how to
set recycle with full auto setting?

Thomas
 

·
Registered
Joined
·
3,761 Posts
HARDROCK said:
I guess I've never be a "Super Senior Member" giving such wrong information as I did...

Separate or not, TRY turning on the rear second half of the one and only same overall air conditioner system and see it it helps your problem.
Your answer wasn't necessarily wrong. Depending on what you've got the temp set to, using the rear AC manually @ max fan and max cool could be colder than the fronts.
 

·
Registered
Joined
·
3,761 Posts
thomas said:
I have no problem with the AC. However, I do have
some issue about the control. I would like to use
the full auto to keep the temperature. But when
the temperature reach to the setting level, it automatively
set the recycle back to use the outside air. When outside
temperature reach 100s, I think it is waste to use
outside and I dn't want to turn on the AC always On
by turn off the full auto. Does anyone know how to
set recycle with full auto setting?

Thomas
Set desired temp, press full auto, press RECIRC. Everything will be automatic EXCEPT recirc as you've now set it. I think.
 

·
Registered
Joined
·
476 Posts
TheWorm said:
Your answer wasn't necessarily wrong. Depending on what you've got the temp set to, using the rear AC manually @ max fan and max cool could be colder than the fronts.
Actually that's a good point as the front system will mix hot/cold in accord with the temperature set on semi-auto when the rear unit is enabled. However, if the front system is set to 60 degrees in full auto or semi-auto, the system runs at full cooling and does not regulate the interior temperature. (See 2003 owner's manual p. 136) Under that operating condition, I don't know that using the rear would make any difference as the A/C system's cooling capability would then be maxed out. I'll give it a try tomorrow. It's supposed to be a hot weekend (temperature--not social life).:)
 

·
Registered
Joined
·
8,866 Posts
In my own non-scientific method, when I turn on the rear A/C, it does seem to cool the car down quicker
 

·
Moderator
Joined
·
3,109 Posts
Relative Humidity?

lewjdw said:
My air conditioner doesn't seem as cold as it I think it should be. Granted, I live in Phoenix where it hit 117 this week but I don't think my MDX cools as well as my other 3 (non Acura) vehicles do. Anyone else whining about this?
What is the humidity there? I believe it is a factor. If it is low, it'll seem like the ac is low on freon and isn't cooling as much as it should. Whereas when it is 90%+, the ac turns the inside into a meat freezer within minutes. Just my experience....
 

·
Registered
Joined
·
1,506 Posts
I have had comments about how fast the "bus" cools down. It was 90% here with 87% humidity and it cooled in 1 1/2 minutes. I did notice that my rear A/C was blowing and I didn't have the RR AC button pushed. Does that just allow seperate control. I have never sat back there. Crazy huh????? I love how the system cahnges the fan speed automatically. Great system.
 

·
Registered
Joined
·
78 Posts
TheWorm said:
Set desired temp, press full auto, press RECIRC. Everything will be automatic EXCEPT recirc as you've now set it. I think.

It maybe a problem with my car. I try the sequence as you described. However, when I press RECIRC, the full auto shift
to auto only automatively. And someone mentioned before
that with auto and RECIRC, the AC is always ON instead of ON
and OFF.

Thanks,
Thomas
 

·
Registered
Joined
·
3,761 Posts
thomas said:



It maybe a problem with my car. I try the sequence as you described. However, when I press RECIRC, the full auto shift
to auto only automatively. And someone mentioned before
that with auto and RECIRC, the AC is always ON instead of ON
and OFF.

Thanks,
Thomas
That's how it's supposed to work. If you press ANYTHING after it's in FULL AUTO, the display will change to just AUTO, meaning everything except what you've just pressed will still be in AUTO mode.

The compressor is running all the time if the display shows auto or full auto; it'll just blend in warmer air depending on the extent to which it thinks you need cooling.
 

·
Registered
Joined
·
1,724 Posts
HARDROCK said:
My X cools MUCH faster when I remember to turn on the back air conditioner by pressing the the "rear manual" button, with the rear fan on "high" and the temp on max "cold".
Hardrock,

Unless there's a BIG difference between your X and my '01 X, the rear unit runs on automatic, just like the front does, UNLESS you press the "rear manual" button; then the rear unit runs at the speed, temp, and air direction that is set on the rear controls. Thus, you're not "turning on" the rear unit, you're just shifting it from automatic to manual.

BTW, I don't use Full Auto, as I don't like the fan speed and air direction changes, but I think the unit cools relatively slowly; maybe I'll remember to have the dealer check it next time I'm in for service.
 

·
Registered
Joined
·
1,453 Posts
I have to agree....

frostyra said:
........... but I think the unit cools relatively slowly; maybe I'll remember to have the dealer check it next time I'm in for service.
.....that the A/C in the "X" does take a while to cool. However, once it gets going, it does make the interior nice and ICE-COLD, but I haven't yet had a chance to try it in outside temps over 85. It probably has something to do with the fact that it has to cool such a large interior area!
 

·
Registered
Joined
·
476 Posts
frostyra said:

Hardrock,

Unless there's a BIG difference between your X and my '01 X, the rear unit runs on automatic, just like the front does, UNLESS you press the "rear manual" button; then the rear unit runs at the speed, temp, and air direction that is set on the rear controls. Thus, you're not "turning on" the rear unit, you're just shifting it from automatic to manual......
I cannot address the 01 or 02 model year. However as for the 03, quoting the owner's manual at page 143:

"To enable the rear A/C passenger control panel, press the RR A/C Manual button on the control panel. The light in the button will come on."

Quoting also from page 143:

"When the system is in FULL AUTO, the rear A/C passenger control panel cannot be used. The system will cycle on and off automatically to bring the interior to the set temperature."

So in summary, you must enable the rear passenger controls (at least as to the 03).
 

·
Registered
Joined
·
1,724 Posts
norcalchuck said:


I cannot address the 01 or 02 model year. However as for the 03, quoting the owner's manual at page 143:

"To enable the rear A/C passenger control panel, press the RR A/C Manual button on the control panel. The light in the button will come on."
Same as on the '01-'02 models. If that button is NOT pushed, the rear A/C functions automatically, following the same settings that the front A/C is using (if you don't believe me, stick your hand back there and feel what it's doing). If it IS pushed, the rear A/C follows the control settings of the rear passenger control panel. Either way, it IS an A/C, and it IS working.

Quoting also from page 143:

"When the system is in FULL AUTO, the rear A/C passenger control panel cannot be used. The system will cycle on and off automatically to bring the interior to the set temperature."

So in summary, you must enable the rear passenger controls (at least as to the 03).
You must enable the rear passenger controls in order for them to control the rear temperature, fan speed, and air-outlet choice. You do NOT have to enable the rear passenger controls in order for the rear A/C to work -- if the front A/C is working, the rear A/C is working. So the RR A/C Manual button doesn't turn the rear A/C on or off, it just chooses between having the rear A/C function as the front A/C does, or giving it its own separate A/C controls. That button only enables the rear controls, not the rear A/C. Honest!
 
1 - 20 of 43 Posts
Top