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These Jeeps have problems with the blend doors...most likely the heat doors are opening up when they are supposed to be closed allowing hot air to mix in with the cold...feel under the glovebox area to see if the heaterbox is hot to the touch when the Jeep is warmed up good.

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Thank you, Drain is clear and the orfice tube was supposed to have been serviced/replaced. Also, when the vehicle is idling, the metal line between the expansion valve and evaporator frosts up and then thaws every few minutes but when the engine speed increases this same line frosts up again and appears to stay frozen until engine returns to idle.

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the coolness slowly goes away and the air flow seeems to slow down.

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Thank you, Drain is clear and the orfice tube was supposed to have been serviced/replaced. Also, when the vehicle is idling, the metal line between the expansion valve and evaporator frosts up and then thaws every few minutes but when the engine speed increases this same line frosts up again and appears to stay frozen until engine returns to idle.

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I dont remember what system your Jeep has as I would have to look it up. But if it is an expansion valve system there is no line between it and the evaporator as the expansion valve bolts right to the evap line at the firewall. Do you mean the condensor and exp valve ? Now if it has an acumulator it would be an orfice system as Mopar does use the orfice system on many of the cars and trucks but not all of them. There may even be a TSB about the evap freezing as I remember a few where we had to flash the PCM as the AC programing was wrong. Sometimes the PCM would even set an AC code because the PCM controlls the compressor cycle. You might call your local Mopar dealer and ask them if there is a TSB about it because I dont remember if your Jeep is one of the ones that the TSB refers too. Ron

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Thank you, Drain is clear and the orfice tube was supposed to have been serviced/replaced. Also, when the vehicle is idling, the metal line between the expansion valve and evaporator frosts up and then thaws every few minutes but when the engine speed increases this same line frosts up again and appears to stay frozen until engine returns to idle.

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I dont remember what system your Jeep has as I would have to look it up. But if it is an expansion valve system there is no line between it and the evaporator as the expansion valve bolts right to the evap line at the firewall. Do you mean the condensor and exp valve ? Now if it has an acumulator it would be an orfice system as Mopar does use the orfice system on many of the cars and trucks but not all of them. There may even be a TSB about the evap freezing as I remember a few where we had to flash the PCM as the AC programing was wrong. Sometimes the PCM would even set an AC code because the PCM controlls the compressor cycle. You might call your local Mopar dealer and ask them if there is a TSB about it because I dont remember if your Jeep is one of the ones that the TSB refers too. Ron

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Thank you for responding, This system has an accumulator and orfice tube. I think the problem is that the compressor is not cycling at higher rpms (highway driving) at idle, you can hear the compressor load up and shut off. At the same time the high pressure line between the orfice tube and evaporator frosts up and then thaws at regular intervals. When the engine speed is advanced to about 2000 RPMs, the frost thaw cycle seems to stop. At this point the bottom line stays frosted and eventually, the accumulator and metal portions of the low pressure lines will frost over. There is a switch on top of the accumulator, does it control the compressor cycling?

Thanks again,

Russ

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That is true as I looked at the TSB's also. I remember some of our cars had a TSB for evap freezing at highway speeds and the fix was a PCM flash to reprogram the clutch cycle at highway speeds. But it does not apply to your vehicle. Usually on orfice systems if it is low on freezon you will see a line under the hood freezing up also. Its the line right after the orvice valve tube. The switch on the accumulator is a cycle switch but it may have another also. If it cools good and cycle's fine at low speeds you might try replace the pressure cycle switch on the accumulator. Ron

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That is true as I looked at the TSB's also. I remember some of our cars had a TSB for evap freezing at highway speeds and the fix was a PCM flash to reprogram the clutch cycle at highway speeds. But it does not apply to your vehicle. Usually on orfice systems if it is low on freezon you will see a line under the hood freezing up also. Its the line right after the orvice valve tube. The switch on the accumulator is a cycle switch but it may have another also. If it cools good and cycle's fine at low speeds you might try replace the pressure cycle switch on the accumulator. Ron

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Thank you Ron, We have a new pressure cycle switch ordered from Chrysler, hopfully, this will solve the problem. I'll let you know.

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Did you replace the High or low side pressure switch? My gut tells me the High side switch is bad, but for the cost you may replace both.

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