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AC is not blowing cold at all. Here is what's happening: the compressor stays on like it should. The line coming out (high) is very hot going into the condenser, and very cold coming out of the orifice valve and into the evaporator. The low pressure coming back out is lukewarm. All sounds good, right? Seems like everything is circulating as it should. But there is no old air whatsoever inside the cab. Pressure is a tad bit on the low side, but within the working zone, so it should at least have some "cool" air coming out. If I change the temp to hot, hot air flows just fine, so I'm guessing the blend door is working. But why no cold air? Are there two doors? Is there a one for the AC that could be stuck shut? Where do I begin?
Blend door actuator go south? Getting water puddles under it? May have a mouse nest in the evaporator box. I had that happen once with a Cadillac. And yes old people owned it, and it sat in their garage more than it was ever driven.
i also think that you have a blend door that isnt operating properly. it might work nicely with the heater, but not so well with the a/c. it might be a bad actuator preventing the door from opening properly in the correct direction.
another issue you might have to deal with is the evaporator core freezing over. you mentioned system pressures being a bit low but still in the operable range, that leads me to think the evap core is in fact freezing over and blocking air from flowing through it properly. it doesnt have to fully freeze over to cause the problem you have. a partial freeze over will allow enough air to come out of the vents, but it will be luke warm because the core cant exchange enough air to remove enough heat from the cabin, so you feel warm air flowing out the vents.
one more possibility, though it is rare that it happens, the refrigerant might have gone sour. it happened to a friend of mines car once. it wouldnt blow cold air, but once the system was serviced, and fresh refrigerant installed, the air was blowing ice cold again.
Pretty simple to diagnose. Take the heater hose off of the heater core so that it doesn't get hot. You can reroute it back to the engine or plug it. If it gets cold, the blend door is sticking open. You can fix this two ways. You can take it to the dealer and have it fixed with new parts. Or, you can go to Lowes and buy a quarter turn valve and put it inline in the hot side of the heater hose. You can then turn off the hot coolant from the heater core and when you need heat during the winter, just turn it on. Costs less than 15 bucks with the valve, fittings, and hose clamps.
Pretty simple to diagnose. Take the heater hose off of the heater core so that it doesn't get hot. You can reroute it back to the engine or plug it. If it gets cold, the blend door is sticking open. You can fix this two ways. You can take it to the dealer and have it fixed with new parts. Or, you can go to Lowes and buy a quarter turn valve and put it inline in the hot side of the heater hose. You can then turn off the hot coolant from the heater core and when you need heat during the winter, just turn it on. Costs less than 15 bucks with the valve, fittings, and hose clamps.
x3 - since you say '...The low pressure coming back out is lukewarm...' leads me to think evap is being hit with HOT air from heater coil.
IF evap was froze over or blocked with leaves/rats nest, the low pressure coming back out would be FREEZING COLD and it's not, so the evap is 'giving up its cold' somewhere.
Sounds like air blend is stuck in 'defrost' mode (heating air with AC on to 'dehumidify' )
On old Mopars, what I find a lot of time is that the foam used to seal the hoses and passages for HVAC crumble, blowing air everywhere except the vents. Check around the dash for stray air.
Dodge has a check valve that is supposed to cut AC at full throttle. Both both my ram and Dakota had issues and needed a check valve replaced. The check valve is a vacuum check valve. On my Dakota it was somewhere around the firewall at the steering column.
Dodge has a check valve that is supposed to cut AC at full throttle. Both both my ram and Dakota had issues and needed a check valve replaced. The check valve is a vacuum check valve. On my Dakota it was somewhere around the firewall at the steering column.
Interesting... But wouldn't it shut the compressor off? It stays on.
Some major shops, like pep boys will give you a free check and estimate, just saying.
Also, is air blowing in as normal, maybe you have accumalation from the fall/ winter? Are your freon levels ok?
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