96 GC suddenly lost AC cooling

Lost cooling in my 6cyl '96 GC without warning this weekend. Fan works, condenser turns on and off, low pressure line is very cold and condensation forms on the line. Air coming thru vents might have a higher humidity level when the AC is turned on than when it is off. Towed a 2500lb trailer last week for the first time, 400 miles thru the hills of Pennsylvania and AC was working fine. Any ideas? just turned 100K miles last week.

Reply to
Hikers
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Hikers did pass the time by typing:

If the compressor cycles properly my first thought is vac leak. Clicking on/off real rapididly means you could be low on 134a.

Is it an auto or manual AC system? The auto has diagnositcs and doesn't use vac for much. The maunal uses vac for almost everything except the blend air door.

Does it blow well? If not you might have mold buildup clogging the coil.

I don't have the specifics for the 96 but it should be similar in layout to the 93.

Reply to
DougW

condensation

I had the same problem with my 95 ZJ and had to replace the orifice tube. If you need one, I have a spare I would like to sell.

Mike

Reply to
WMS

Thanks DougW. Checked out your LED turn signal add ons on you site, Nice.

System is manual AC. Low side pressure is 65 when engine is off. Cycles from

10 - 45 w/AC on. Clutch kicks in when pressure hits 45 then as it begins to drop clutch stops. This is all of about 5 -7 seconds. Fan pushes air well and heat settings work fine. Hikers w/Humid Jeep
Reply to
Hikers

Hikers did pass the time by typing:

Measuring from the low-side is tricky. The recommended method is measuring the high side, drain and fill, or temperature difference on the evaporator feed and return lines.

40-50 PSI low-side is "normal" for most cars.

The only guides I have are for the high pressure side.

Ambient Temp Compressor discharge pressure

60 F 220 psi 70 F 240 psi 80 F 260 psi 90 F 300 psi

And temperature differences between evaporator inlet and outlet should be 8-10 F (5-6 C) with the outlet colder than inlet.

Reply to
DougW

Reply to
Hikers

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