Hello All,
I have a 2005 Ford Explorer 8Cyl 4.6 4x4
The A/C running cold one day, next morning hot. No signs of trouble, like not getting as cold or clicking sounds. The list of troubleshooting clues are:
- Hissing noise at the rear Aux blower fan, maybe the lines below the motor.
- The self test, where you press the OFF and FLOOR buttons simultaneously shows no DTC's
- Low pressure line fluctuates from low reading to high, like maybe the clutch is not working.

The hissing noise in the back is throwing me off. I will check after work to see if the compressor is engaging, but I was hoping someone had a similar problem and can help shrink the list of possible issues.

Thank you

 

As far as the list of causes, you are ahead of the game by going by what you have and don't have.

So,,,,,,,,,,,,, help us out here,
You must have gauges connected to know if the reading is going from low to hi.
If that is so,,,,,,,,,,,,that could mean the compressor is engaging and pulling down the reading ,which it should do by the way, only possibly due to a low charge it is cutting off.

When you get a chance to check, turn the AC on MAX and watch what the compressor does. If it goes on and off quickly, there is a good chance the system is just low on refrigerant at which point you might adorn your safety glasses, hook up a can with hose connector and start adding refrigerant . Container must always be in the upright position so only GAS goes into the .LOW Side as the compressor is running. The frequency of on/ off cycles should drop as sufficient refrigerant enters the system. NEVER allow the container to tip because if it does it will allow liquid refrigerant to go into the compressor and wreck it ! The compressor is designed to compress GAS and not liquid.
The system should cycle on and off one or two times a minute. You don't want to overcharge the system because that can affect cooling efficiency.
Let us know how you make out with this, thanks

 

Thank you for the response, it is appreciated.

I was hesitant to add refrigerant at first because the low pressure was bouncing above 50.

The compressor is engaging. So from your post, the low pressure was dropping below 15, the compressor was kicking on, then the pressure would get to 60 and the compressor would disengage. This process would repeat quickly.

Since then I added 20oz of R-134a (safely) and now the cycling process is: Compressor engaged- build up to 40, compressor disengaged – slowly drop to 25. Stays at 25 for about 10 seconds, then start all over again.

Clearly adding made a change, and I am glad the compressor works. What concerns me is the amount of refrigerant was added and still needs more. But this was a process of elimination to help isolate where the problem is. I might be chasing a leak and do not have the proper tools. The Explorer, with rear A/C, has lots of lines to check.

 

Technically,,,,,,,,,,,,we are supposed to repair any leaks before bringing to proper charge. I just know you are going to do that. Until you can find and correct the leak ,,you may need one or two cans to find it. Who knows it may stop leaking some day, just don't hold your breath. Can't give you bad suggestions so , the rest is up to you.

 

Update, sorry been busy. So the A/C has a charge and holding. I ordered a blend door for the Aux unit located behind the rear seats on the drivers side. It was clicking and when I unplugged it the clicking stopped. The gears did not look stripped.

I currently is only blowing semi cold in the front passenger vent, slightly warm on the drivers side. I installed a new blend door on the drivers side, but i don't think that was the problem.
The fan blows the air (not a/c air) from floor, head, and defrost locations when hitting the controls. It even responds to left and right blower speed when you turn on the fan at high to low speed. on the driver and passenger side. (duel control aux).
What happens is that if I turn the heat up high, it only blows out the drivers side. If I switch to A/C, it only works on the passenger side.
I would like to know if there is another blend door that I am not seeing. I only see the LH and RH blend door on the box near the footwells. I have a Chilton's manual which might be useless.
Any other items to check> A/C blower motor?

 

update: I installed the rear blend door (behind the rear seats, drivers side) and no more clicking and the doors seem to operate as designed.
for the front A/C issue, (hot driver/semi cold passenger side), I removed portions if the center counsel's and the plastic ducts that feed the center airflow to the floor. I was able to feel the RH and LH door blends and switched from heat to a/c. both doors are working as designed. Wherever I tell the airflow to go (head, feet, windshield) all work. Therefor the lack of cold air from the A/C to the front is from another issue. I am thinking to check the following next:
- Front A/C Blower. I do hear it click on when turning on the A/C, but will investigate further.
- Clogged A/C lines. (flush) Not sure how to test this, might have to take it to a professional.
- A/C Compressor, it does engage and filled with no leaks.
- I tested the vacuum valve that cuts of the coolant to the heater core, and works as designed.
- I went through the fuses and relays, all seemed ok.

Any other suggestion?

 

Update: Issue A/C not blowing cold in the front (warm Drivers side/Semi Cold Passenger side) and Cold in the rear (DATC).
I hooked up my gauges, and this time I measured the high side. In retrospect I should have checked the high side sooner. My reading are 225psi (high side)/ 50psi (low side). According to charts my problems might be:250 PSI / 30 PSI = You have air somewhere in the system.

250 PSI / 50 PSI = The system is overcharged and the condenser is not cooling. Condenser may be blocked.

The A/C line that the High side is attached to is definitely hot.

my next steps are to rent the required tools to drain the A/C system and flush it. I will also replace the accumulator while the system is empty.

I should have checked the high side sooner, I thought since the refrigerant was low in the beginning it just needed to top up.

Anything else I should replace when the system is empty?

 

Run a vacuum pump on it to purge the system of air.

 

Ok, went to a local shop and had the refrigerant removed..

My question is when Flushing the A/C system, what parts do I avoid? I will disconnect the A/C compressor and accumulator (replacing). anything else that can't be flushed? Any good write-ups for a 2005 Ford Explorer with DATC?
I did a search in this forum and can't find a A/C Flush specifically. Any components to avoid flushing?

 

Going to change the condenser as well. Looks to be the original and the system is discharged (empty).

Does anyone know what the yellow vacuum hose under the center counsel controls? seems to disappear into the center of the box. I traced all the other vacuum hoses to their locations and all work as designed.

I also put a vacuum line on both high/low A/C ports. went below zero and stayed there. no apparent leaks.