AC Still Not Cold

I just got done ripping down the dash and replacing my heater core, and the more pertinent concern with rising temps in Florida was the evaporator. My AC has not worked in over a year. I charged it last year, got cold for a day then I leaked out. Figured this was the evaporator due to the entire system being replaced before I purchased the Jeep. There were no signs of anyone entering the dash and the evaporator looked factory so I felt like I was on the right track.

Fast forward to today, after buttoning up the console I gave the system a charge (I know the correct way to do it is to put a vacuum on the system but I'm checking for leaks more than anything at this point). The compressor instantly started cycling upon charging (22oz). It was cycling on and off, which mean the system was low but the air was slightly cooler at this point. Not cold, but than hot air. I went ahead and put another can in it (14oz). The compressor is no longer cycling but the air is still not cold.

This is what has me stumped, the evaporator and accumulator are cold as ice. The blower should be blowing the cold air off the evaporator into the cab as cold air if I understand this correctly. The blend air door is suspect, however, as I move the control from hot to cold it is moving. Perhaps it is not moving enough to open up the cold side? About 30-35 degrees. I would think that it would still allow enough cold air, judging from the temperature of the evaporator to still feel cold to the touch but alas it is not.

Looking for ideas of where to go from here. I'm thinking I should take the blend motor off and manually adjust the blend door as a trouble shoot. I am wondering if the blend door somehow got reassembled out of place on the top side allowing too much hot air to get in?

The system seems to be holding a charge. Blend door and blower motors functioning properly. Where the heck do I go from here?

you don't feel any air? or the air isn't cold?

Didn't evacuate it, then overfilled it.

It ain't going to blow cold this way.

Pull vacuum and hold it to boil out the moisture. The longer the better.

Then add 1.25 lb of R-134a.

Might have a frozen evaporator. Damaged temperature switch? There's supposed to be a little thermal switch by the evaporator that turns off the compressor when temperature hits 45f. That is what makes the compressor cycle--if you run the fan on low on a cool day then there is not much thermal transfer and the switch activates often, but if you run the fan on high on a hot day it will stay busy but still turn off to protect itself.

md21722 said:

Didn't evacuate it, then overfilled it.

It ain't going to blow cold this way.

Pull vacuum and hold it to boil out the moisture. The longer the better.

Then add 1.25 lb of R-134a.

Click to expand...

THIS.
With air and moisture in the lines you're just destroying parts.
I refilled mine last month, as my evap is suspect also (every other year I have to charge, and have new parts save compressor), and I have a known bad heater core (bypassed currently). Dread pulling the dash...

Assuming you have a newer model, it takes only 20oz.

1. Pull a vacuum with a proper manifold and gauge set.
2. Hold vacuum for 15mins at least.
3. Pull another vacuum for at least 15-30mins.
4. Hold vacuum for at least 30mins.
5. At this point, the needle on the gauge set SHOULD NOT MOVE.
6. Attach can of r134a to fill line on gauge set, purge air from fill line by loosening slightly until a bit of Freon vents.
7. Fill system with 20oz, and ONLY 20oz, of nice r134a - I use AC Pro or Dupont Suva

I'm pushing 45* from the vents steady - driving on trips it dips to below 40*

Everyone else beat me to it, you'll not get cold air with non condensibles in the system.

Couldn't hurt to replace the accumulator (filter dryer, whatever) before you evacuate it, they're cheaper than the charge of refrigerant and remove moisture from the system. If it's been open for any period of time, the desiccant will saturate with atmospheric moisture. Once moisture hits the expansion orifice, it freezes and the system ceases to function.

X2 on the longer vacuum comment.