08 Explorer Eddie Bauer A/C Problem

[RR26101]

Hi there. I'm having an issue with my A/C. While running A/C through the console vents everything seems fine until you accelerate. Then it starts blowing through the defrosters. Sometimes shortly after you stop it starts blowing through the console vents again. Then after accelerating again it goes through the defrost vents. It only does this while on A/C. The heat seems to work fine and will blow through whatever you select. While on A/C nothing will change it. If you select another function and shut it off then turn it back on it will blow through the other vents. Just not quite sure whats going on here. I've only had it a few weeks and am new to the Explorer. Any advice on what to look into will be greatly appreciated.

 

[94Eddie]

It is a cheap, easy fix. You have a bad AC control valve. This valve is one way and it keeps the vacuum reservoir from losing vacuum when the is engine not creating vacuum when under acceleration. A link to the part is below. The valve is located near the firewall on the passenger side of the engine bay. It isn't hard to track down or replace. Just make sure the valve is installed in the right direction since it is a one way part. Take note of how the old valve was installed.

Amazon.com: Genuine Ford XR3Z-19A563-AA Air Conditioner Control Valve: Automotive

 

[RR26101]

It is a cheap, easy fix. You have a bad AC control valve. This valve is one way and it keeps the vacuum reservoir from losing vacuum when the is engine not creating vacuum when under acceleration. A link to the part is below. The valve is located near the firewall on the passenger side of the engine bay. It isn't hard to track down or replace. Just make sure the valve is installed in the right direction since it is a one way part. Take note of how the old valve was installed.

Amazon.com: Genuine Ford XR3Z-19A563-AA Air Conditioner Control Valve: Automotive

Thank you for your response. I have went out today and taken a look around under the hood. What I have found is there is what appears to be a vacuum line coming out of the firewall on the passenger side right near the a/c systems part there that has the low pressure port you use to recharge it. It is not connected to anything it's just hanging there. Now on towards the front of the engine bay on one of the heater hoses it looks like this is the opposite end of that line. There's a thing there with a vacuum line on it that is taped to one of the hoses that appears to run into the firewall to the heater core and it also is not connected to anything. So these two look like they belong together. The vacuum hose at the end towards the firewall goes into a rubber piece that has another line also going into it. Behind the glove box this would all be in behind the blower motor it appears so my question if you would know the answer is this. Am I correct in assuming that those two go together and is this a line I can replace just being under the hood or am I about to have fun in the adventures of having to remove the blower motor and all that fun stuff behind the glovebox? I am really hoping I can just pull that rubber boot that both those hoses are going into and replace the line from under the hood and hoping that this is the vacuum line that operates the mode door that is causing my problem. In the pictures included below it is the second hose that is gray that is connected to nothing and the second picture is the part on the heater lines that is also connected to nothing.

 

[Rcflyer330]

That is the heator control valve not what you are looking for. When you turn the dial to cold the coolant flow to the heater core is shut off from that valve. You are looking for the check valve it will be near the hood at the back of the engine bay. I will get a picture of where it is at on my car.



Ok in red is the ac check valve that you are looking for in blue is about where the heator control valve is that you took a picture of.

Also can you get picture of what you are talking about with the vacuum lines and ac lines.

 

[RR26101]

Ok mine was in the same place.... Kinda feel dumb on that one. Now is there a way for me to check it and make sure that is my problem? I mean I took it loose and did have a vacuum on it as I heard it suck air as I took it off.

 

[94Eddie]

You should be able to blow through in one direction but not the other.

 

[Rcflyer330]

What 94Eddie said.
Just to add I would just replace it sometimes the check valve will test fine by blowing on it but when its in the system it will fail. They are not much money and eventually it will requre replacement. Test it with both light pressure and medium pressure. It should stop air one way even with a light pressure on the valve.

 

[RR26101]

What 94Eddie said.
Just to add I would just replace it sometimes the check valve will test fine by blowing on it but when its in the system it will fail. They are not much money and eventually it will requre replacement. Test it with both light pressure and medium pressure. It should stop air one way even with a light pressure on the valve.

Ok I was thinking that as well. I did test it this way and it does let air only flow one direction but again I am not sure how it behaves while connected to the system. Just out of curiosity if this does not fix the issue what should I look at next?

 

[94Eddie]

Ok I was thinking that as well. I did test it this way and it does let air only flow one direction but again I am not sure how it behaves while connected to the system. Just out of curiosity if this does not fix the issue what should I look at next?

You could could have a slow vacuum leak elsewhere in the system that isn't bad enough to prevent a vacuum in the HVAC system when the engine is producing a vacuum. In this case it is best to do a smoke test. Typically, the AC valve is the problem for the way your system is behaving. I would, and did, spend the $10 to replace the AC valve. Doing this solved my problem which was identical to yours.

 

[jeffb222]

It is a cheap, easy fix. You have a bad AC control valve. This valve is one way and it keeps the vacuum reservoir from losing vacuum when the is engine not creating vacuum when under acceleration. A link to the part is below. The valve is located near the firewall on the passenger side of the engine bay. It isn't hard to track down or replace. Just make sure the valve is installed in the right direction since it is a one way part. Take note of how the old valve was installed.

Amazon.com: Genuine Ford XR3Z-19A563-AA Air Conditioner Control Valve: Automotive

Thanks for posting this! I have the same problem and did a quick google search and it brought me directly here. I can blow through the valve in both directions. Ordered

 

[jeffb222]

It is a cheap, easy fix. You have a bad AC control valve. This valve is one way and it keeps the vacuum reservoir from losing vacuum when the is engine not creating vacuum when under acceleration. A link to the part is below. The valve is located near the firewall on the passenger side of the engine bay. It isn't hard to track down or replace. Just make sure the valve is installed in the right direction since it is a one way part. Take note of how the old valve was installed.

Amazon.com: Genuine Ford XR3Z-19A563-AA Air Conditioner Control Valve: Automotive

94Eddie - thanks for posting this. I have the same issue and a quick google search brought me directly to your answer. I popped my vacuum control valve out and can blow through it both ways with no effort.

Ordered and anticipating a very inexpensive fix! Thanks again