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Front ac not blowing cool enough air but rear working fine

64K views 21 replies 18 participants last post by  persicaso1 
#1 ·
It just started to notice that my 2004 Honda Odyssey's front ac is not as cool anymore (wife is driving it most of the time) but the rear ac is working. I have this van for the last 7 years and has been working fine (ac) all along. I believe all the switches are working, as when full auto is on, the light will go on and will come off if the desired temperature is reached when rear ac is working. Has anybody have similar issues before?
 
#3 ·
It just started to notice that my 2004 Honda Odyssey's front ac is not as cool anymore (wife is driving it most of the time) but the rear ac is working. I have this van for the last 7 years and has been working fine (ac) all along. I believe all the switches are working, as when full auto is on, the light will go on and will come off if the desired temperature is reached when rear ac is working. Has anybody have similar issues before?
Hmmm, I noticed this just today in our 2003 EX. Cabin air filter is fine. The front AC does not seem as cold as the rear AC. Outside temp is a moderate 85F, with 30% humidity. Do you notice this disparity most at idle with the A/C on? Does your condenser fan (passenger side) spin at high speed?
 
#4 ·
AC sort of stop working - Please HELP we are in the middle of our trip

First is if this is a repeat I apologize.

Car is the 2003 EXL-Entertainment hardly used 70k miles

We are in the middle of our road trip from NJ to Chicago (heatwave). Somewhere between Cleveland area and Toledo on I-80 the AC stopped working. *i am talking about the dial is at 60 and fan is on high. *First thing I notice was that the sound of the fan sounded strange and it was not coming out from the front vents and the air that was coming out was not cold.

So I pulled into the rest area to give it a quick check and also search for some answers. *I find a Honda dealership just 35 miles away, and it is on our way, perfect.

so we all jump in thinking I know what the part that I need and the dealerships parts dept. has it. *On our way there, I have the climate settings at 60 and fan is high, output is still warm air, but this time it is coming out from the vents. *In the middle of this leg, my son complained that it was hot in the back so I turned the rear control to AC. *Next thing you know, the entire system, front and back is working normal. *It is now blowing string AC running air in the front and back.

So what went wrong?

Is it that I need freon?

Is it the Transistor Assy (Autozone Blower Motor Resistor)?

is it the head unit?

is it the cabin filter? This car might be old, but we only have 70k on it. Changed only once, and I have been meaning to do it myself this time.

Can this wait til i get home or should I do something now?

Part good news is that we made it to Chicago. *I did stop at the dealership, but did not buy the Transistor. *They couldn't do anything to the freon, because they were closing in 30 minutes. *I do feel the system struggles to get cold air, when it does, I turn the rear control to cold and both systems starts spewing cold air. *That's almost like saying my wife is here and happy, but she is truly happy but when we go shopping. *Sorry ladies.*
 
#5 ·
UPDATE:
Made it back to NJ.

While in Chicago, I did change the cabin filter. Air is blowing through the front vents. I still sense that the air does not get cold like it use to. When the car is idle the air is not as cold as it use to be. It only gets very cold when we are on the road. I also sense that putting on the rear ac seems to help the front get colder.

Do I need to change the transistor?


Please help.
 
#7 ·
It only gets very cold when we are on the road.
This statement makes me think you may be low on refrigerant or your compressor is going out(hopefully not). When driving, the compressor will run at a higher speed and create more pressure. In a normally operating system you should not notice the air get colder when driving vs idle.

If you eliminate all the potential a/c control problems then you might try and take it to a shop. They can hook up gauges to your system which will tell you a lot about how it is performing.
 
#6 · (Edited)
If the front AC is warmer than the rear I would check the valve that allows coolant to circulate through the heater core.
Have some in the van adjust the temperature from fully hot to fully cold and watch it move.
It is under the hood on the firewall. Here is a picture of it in my 2001 EX. That ignition coil is #2 in the picture. As you can see my valve leaks a little.
 

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#8 ·
My statement above was for the original poster regarding the valve on the firewall.
For the post jacker lpvn I would make sure your AC fan behind the radiator is working. Actually there are two fans. I think that they both should come on when the AC is working. You should also hear and see the compressor cycling on and off (not quickly) if those are working.
 
#10 ·
The A/C also shuts off temporarily when you floor the accelerator to pass for example.
 
#11 ·
I have a 2000 Ody EX with ~153k miles on it and every now and then I notice two things:

1. The fan itself won't come on - or takes a while to come on - this occurs whether the fan is on Auto or you set the speed manually.

2. The temp of the air blowing in isn't cold - it's almost as if the climate control system doesn't realize it's 100 degrees and you have it set on 65.

In both cases, I find that if I wait awhile - say 10 to 15 minutes, then it eventually works.

Today my wife told me both issues occurred after leaving the grocery store - the rear fan would run but the air wasn't cooled. After another stop (shut off the car, come back and turn it back on) it blew cool (not cold) air.

Tonight - I recreated the issue and took it to a self car wash and hosed the underside (I read somewhere that the radiator for the AC being blocked may affect it) - not sure if it did the trick - but I left the engine and AC running and when I was done the AC worked great - the fan worked and the temp was nice and cold.

I'm not 100% sure if what I did resolved any issue so I'd appreciate anyone's insight.

I did change the air cabin filter awhile back - not sure if that improved anything but it was the first time I ever changed it (yes, I'm ashamed - I purchased the vehicle brand new 11 years ago).

Thanks.
 
#12 ·
To G8ROdy, ok I'm having the same problem as the OP. Front is hot; rear is cold. I checked the valve and it is not moving, when switching from hot to cold. What next?

Is the climate control panel bad?

What drives the heater control valve, is it some sort of motor that is bad?

Thanks!
 
#13 ·
I would try to see if the cable moves when it is unhooked from the valve. On my 2001 it was a pain to take off (like most things) but not impossible. I would hope the valve is just stuck because that is a whole world easier to fix than any part of pulling apart the dash/climate control.
 
#14 ·
Check the heater control valve this way:
1. On the firewall side, unclip the cable (simply pull the clamp up with a finger), unhook and see if you can operate the valve manually. The lever angled toward the firewall means close and the air should be A/C cold. Angled toward the engine means open for heater core and heat should come out.
2. If the valve is fine, watch the unhooked cable and see if it moves when changing the temp dial from 60 to 90. If it moves only slightly, you need to lube the cable -- unhook from other end (near passenger footwell), lube with hi temp grease on the firewall end and fully work the cable. The travel should be quite a bit at full -- almost 1.25 inches, I believe.
3. If the cable does not move at all when adjusting the temp, go to the passenger footwell and look for the blue cable. It is held by a clamp. Simply pull off the clamp and unhook from the air mix motor. Does the motor move when changing the temp from 60 to 90 (ignition switch on II)? If so, lube the cable and reseat -- first at 60 on the temp, hold the end of the blue jacket at the plastic stop, hook the loop to the air mix motor and slide the jacket into the clamp. On the firewall side, angle the valve lever toward the firewall, hook the loop, pull up the slack toward the firewall, and clamp the blue cable.
4. If the air mix motor does NOT move when unhooked, the motor is bad -- around $200 for this part.

Hope this helps.
 
#17 ·
If your water valve is working and doesnt leak a lot, and the blend door is functioning properly, one guess was that the front expansion valve was clogged...the rear A/C bypasses the water valve...the replacement of the expansion valve may be a last resort because you need to evacuate the system of R134a, go in thru the glove box, remove blower motor, remove evaporator and there it is.
 
#18 ·
Can you explain exactly how to unhook the clamp? The valve lever on my 2001 Ody is parallel with the firewall when on 60F (which seems to be the norm) but I would like to try and move the valve inward towards the firewall - to see if I can get colder air from my AC. It looks like the left side of the clamp is what I am supposed to lift up, correct? Do I just reach under on the left side of the clamp and pull out and up? I'm afraid of breaking the clamp... Once the clamp is up, do I just pull the blue cable casing back towards the firwall to remove the slack, then reclamp? Thanks for any guidance you can provide. Jeff
 
#20 ·
Following
 
#21 ·
The OP's symptoms (cool in rear, not so much in front) are surprisingly common with an under-charged system. As I tell everybody:
1) DON'T use any refrigerant containing sealers - only pure R134a. The kind with oil or dye is OK, but you don't need oil unless replacing certain components. The dye is useful for pinpointing leaks later on.
2) If you're going to do any work on your a/c system, purchase a manifold gauge set (~$50-100) that monitors both the low AND high side pressures. The kits in the auto parts store only monitor the low side pressure. People have blown off their A/C lines with these kits because they didn't realize the high side pressure was going off the charts due to a problem they didn't expect (blockage in high side line for example).
3) Refrigerant doesn't get "used up". The only reason that less may be in the system is because some of it leaked out. Many people would consider that if it took 10 years to leak out that a re-charge may be a sufficient repair. If it's leaking out annually, you probably want to fix the leak.

Just a reminder: The ONLY way to know how much refrigerant is in a system is to remove it all, and weigh how much was recovered. It takes more equipment than most DIY'ers are willing to acquire to do this step. Adding to the system is always a bit of guess work. Know your refrigerant capacity for the vehicle, and never exceed that amount while charging.
 
#22 · (Edited)
I think I think that the expansion valve from the front AC system is Clogged and do not allow that gas goes through and expand to start the termodinamic fase. It doesn't happens at the rear ac so it works very well. Another reason that I think it is because both system works with the same air compressor and the gas pressure is hold well. Just change the front AC expansion valve .
 
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