Help for those of you with intermittent A/C problems

[joezek]

I've had an ongoing problem with my air conditioning system. It works great, gets ice cold, then suddenly cycles itself off for a minute. This process repeats itself constantly. I thought it was moisture in the system, so did a vacuum and recover the freon, reserviced etc. This seemed to work, but the next day the problem was still there. I suspected the forward expansion valve.... so I changed that and the problem is still there.

So today I found this ford TSB reference number 04-5-9. It's titled "CLIMATE CONTROL- INTERMITTENT LOSS OR AIRFLOW FROM A/C SYSTEM AT HIGHWAY DRIVES- VEHICLES BUILT PRIOR TO 3/16/2004".

Well reading through the TSB, the problem is the thermostatic switch is mounted on the expansion valve and it gets too cold, causing the system to shut down before the evaporator has a chance to cool the cabin down.

The TSB provides a kit part # of 4L1Z-19E992-AA which relocates the thermostatic switch to the evaporator core. This prevents the system from cycling on/off so frequently. With the newly mounted switch the system will work like most normal a/c systems do, and only shut off if the evaporator ITSELF gets too cold and is at risk of freezing up.

The standard low pressure switch is still in place so there's no risk of the system freezing and starving the compressor of it's freon.

That kit part # is ok on Google, but not found on Motorcraft website. I'll check the dealer at lunch time to get a price and the kit hopefully.

 

[joezek]

Well found the answer quicker than I thought. Looks like the kit is $153!!! That's ridiculous, paying that much money for something that was improperly designed, so poorly designed that they had to create a TSB for it. It just sucks because since it's not a safety issue they're not forced to fix it at the dealer.

I'm going to see if I can make my own work around for this problem. Either relocate the existing switch which = $FREE. Or possibly just bypassing the switch which also = FREE. All other vehicles I've owned did not have a temp switch like this, they only had the standard low pressure switch, which by the way this system also has. I don't see a need for it at all, and definitely won't be paying $153 to fix Ford's poor design using Ford's kit that was designed to fix their incorrectly designed system.

 

[joezek]

Ok, one last final update: I removed the temperature switch from it's location (mounted on the thermal expansion valve). I left the wiring intact, and tie wrapped the temp sensor to the wire harness near the computer and TXV.

NOTE*: The temp switch is NOT the big round screw in sensor on the expansion valve! The temp switch is located on the bottom forward area of the expansion valve and is held in with a small torx screw. DO NOT ATTEMPT TO REMOVE THE UPPER PRESSURE SWITCH unless you have already removed the freon.

With the temp switch removed and safely tied out of the way, the system runs like any other normal air conditioning system. It still has the low and high pressure safety switches to prevent damage to the compressor, and it still has the cabin air temperature sensor for those of you with electronic climate control.

I just went out for a test drive and it worked perfectly. I'm now able to run the fan at a low speed and it continuously pumps ice cold air. Before what the problem was, the a/c compressor was constantly cycling on/off and the air was just slightly cold. The only time the compressor stayed on before was if I left the fan on full speed, and even then it would cycle when driving on the highway, and I'd get periods of warm air that smelled like a warm refrigerator.

There's nothing wrong with removing the temp switch, obviously since Ford redesigned it and they removed it 3/16/2004 because it was causing problems / complaints.

If you choose to use the Ford TSB, that will also add protection from the evaporator freezing up with ice on the external fins. Some people in humid conditions were experiencing a stoppage of airflow. This was caused by ice collecting on the outside of the evaporator. This really shouldn't be a problem unless the evaporator is already dirty or if the water drain is restricted. But if you have this problem already then I recommend installing the TSB kit.

 

[98Sexpedition]

question, I have a friend with an 03 F150 4x4 quad cab. When the A/C (max) is on, it only blows through the defroster, but when you move the control to Vent it blows through the vents but A/C is off. The only option to run A/C in an 03 apparently is on Max A/C. I've tried all combinations on the controls and none work except Max A/C for the air, and of course defrost. What would cause it to only blow from the defroster?

 

[joezek]

I'm assuming this F150 has a digital climate control and not the standard knobs? I don't have an option for "MAX" on my 03 expedition but I do have the option to recirculate, and another button that says "A/C".

Some vehicles will not let you run the fan in recirculate mode unless the a/c compressor is engaged, thereby automatically engaging the a/c compressor during max a/c (max a/c is the same as recirculate). Also, using defrost automatically turns the a/c compressor on as you already knew.

My 98 exploder has the max a/c option, and the only three ways to engage the a/c compressor were to 1)- push the "Automatic" button and then select a temperature like 70 degrees etc., or 2) the "Defrost" button, or 3) "Max"

When you have it on "Automatic" it will then give you air through the regular air vents, not the defrost vents.

 

[Racenut]

On my '02 EB Expedition with the electronic climate control, I can get A/C to work in the following positions hope this helps.

1. Automatic - set the temp 70 or lower.
2. Max A/C - recirculate in cabin air.
3. Panel & Floor - set the temp 70 or lower ( regular A/C ).
4. Defrost - A/C runs always in defrost.

The only reason I could think of why it dosn't blow from the vents on Max A/C would maybe be a bad vacuum line some where.

 

[Hard2Hear]

Hey Joezek-

Any chance you could update this with a few pictures? I have this exact issue on my 04 Expedition.

thanks!

 

[joezek]

Hey Joezek-

Any chance you could update this with a few pictures? I have this exact issue on my 04 Expedition.

thanks!

I tried and its nearly impossible to get a decent picture without first removing the computer from the firewall again. The expansion valve is mounted on the firewall behind the battery, below the computer. It's hidden by the computer's wiring harnesses. The temp sensor is a small 1 inch black block, it's held in by one torx screw and a plastic black clip. When you remove the torx screw, the temp sensor will pull out, it has a metal probe that sticks into the expansion valve about 3/4".

What is the build date on your 04'?

Again I drove around quite a bit after work and also after changing my fuel filter, the a/c system is working perfectly now. I'm freezing my ass off now even though it's hot outside. The a/c system continues to pump out freezing cold air even on low fan speeds, I love it.

 

[johnny boy]

i just went through a problem with my 06 expedition limited....totally vaccum line problems....the lines seem to rot...i thought it was weird for lines to rot so soon...but i had one line go bad from an airbox located behind the battery and going into the firewall...and another line go bad from the aircleaner to the master cylinder of all places...
my original problem was the dash vents would only work intermittently...then eventually they stopped working all together with air only coming from the defroster and a small bit comming through the bottom of the dash...

i also had the plugs and coils changed...they made it to 70k...apparently the plugs are extremely hard to change as ford broke 4 of them in the head and is currently still working to get them out...im promised the truck 2moro
i am putting it up for sale if anyone wants a pretty nice truck fast for a great price...
[email protected]
or hit me up here...

 

[Pollock]

Joezek,
I know this is an older thread, but could you point out which switch needs to be disconnected on the diagram