Front AC hot, rear cold

[retk9]

Puzzling issue with an 04 Exp with manual AC. Front AC suddenly started blowing hot air. Rear AC still blows cold. Replaced front blend door actuator but no change. Gage on AC recharge bottle showed level was low so I added a can. Front AC still blowing hot. Noticed ice build up on low side line but only from the front of the truck until the low side port. No ice from low side port towards the firewall. Any advice before a shop wants to charge me more than the truck is worth?

 

[Hamfisted]

Kinda sounds like your front AC expansion valve is blocked. The expansion valve can also come apart inside, where the shaft detaches from the valve itself. Either way, you have to discharge the system and swap out the expansion valve for a new one and vacuum and recharge the system. Use new O-rings on the lines when you do the work.



https://www.rockauto.com/en/catalog...t+&+air+conditioning,a/c+expansion+valve,6788

 

[TomB985]

Yep, I think hamfisted is on the right track. The only way the low-side line from the firewall would be warm inthat situation is if your expansion valve is plugged. Not an expensive fix if you do it yourself, but recommend having a shop evacuate your refrigerant if they are willing.

 

[retk9]

Expansion valve does make sense. Although I replaced that 2 years ago but that doesn't mean it can't be blocked or broke. Still have to pay for evac and recharge but it that is all it is, not too bad.

 

[BlackCoffee]

Agree, I had the reverse problem. Front worked but aux expansion valve was bad. If one of them is working, you know the compressor is working and the high/low pressure cut-off is not the problem. You will have to open up the system and recharge. If you have a vacuum pump and manifold it is not that bad.

 

[llpbio2]

May I ask where the front ac expansion valve is physically located on a 2005 expedition Eddie Bauer?
I thought it was the one located by the ECM.
Thank you

 

[whtbronco]

It's right behind the passenger side of the PCM. If you stand next to the passenger front fender, at the front of the tire look across the battery ground post and you'll see the valve behind the PCM.

 

[llpbio2]

Thank you that is the one I replaced when I installed a new ac Compressor, condenser, hoses and dryer.
I pulled a vacuum and verified the vacuum held for 4 hours then charged the system the back blows cold but the front hot.
I replaced the blender door motor thinking it was bad which did not help.
I did find a plastic piece when I replaced the compressor and other parts and not sure if it came from the system or not I am attaching a picture of it.

 

[whtbronco]

That just looks like a protective plug for something until it's installed. I'm not certain though.

There's 2 expansion valves in our trucks. The one behind the PCM is for the front A/C, the one for the rear A/C is in the back of the truck above the rear right rear wheel well. I'm not suggesting the expansion valve is the issue, but it is possible and can cause the symptoms you have. Any chance there was debris in the evaporator or any other part not replaced? The expansion valve could simply have gotten plugged up with debris or ice.

This page might help and offers some troubleshooting tips for the expansion valve that do not require discharging the system.

How to Test an Auto AC Expansion Valve: A Step-by-Step Guide

Learn how to test an auto AC expansion valve and diagnose any potential issues with your car's air conditioning system.

ricksfreeautorepairadvice.com

 

[llpbio2]

Thank you very much this will help me.

 

[llpbio2]

I replaced the front expansion valve and the front still blows very hot when I set it on AC, I want to try bypassed the heat exchanger to rule out the engines coolant next looking for an easier area to bypass it at, I tried pinching off the lines but this did not seem to help.