"Max A/C"

[roaniecowpony]

I noted that my AC isn't keeping up with cooling when the temperature is in the 90s or above. I attributed this to my quick and dirty recharge after installing a new engine before a trip. While driving up the San Juaquin valley in upper 90s and above it was not quite cool and relaxing, with the AC blower on the highest setting and the recirculation button lit.

So, today, I thought I'd check the manual for anything I'm missing. It shows that there is a "Max A/C" button on the Uconnect that supposedly does something. I started my JLUR in the driveway and while idling, I couldn't tell the difference between this button on or off. Anyone use this?

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[jeepingib]

I believe it just changes the cycling of the compressor and fans. If you had your system open for a while you really should replace the air drier and have it vacuumed for a solid 30 minutes to eliminate moisture.

 

[GATORB8]

I believe it normally changes to upper dash vents (face?), fan at full, temp at coldest and turns on recirculation.

 

[alphawolff]

I noted that my AC isn't keeping up with cooling when the temperature is in the 90s or above. I attributed this to my quick and dirty recharge after installing a new engine before a trip. While driving up the San Juaquin valley in upper 90s and above it was not quite cool and relaxing, with the AC blower on the highest setting and the recirculation button lit.

So, today, I thought I'd check the manual for anything I'm missing. It shows that there is a "Max A/C" button on the Uconnect that supposedly does something. I started my JLUR in the driveway and while idling, I couldn't tell the difference between this button on or off. Anyone use this?

All max AC does is force max fan speed, lowest temperature, and turns the recirculation on.

 

[grimmjeeper]

All max AC does is force max fan speed, lowest temperature, and turns the recirculation on.

This.

It doesn't do anything more than that.

Double check your cabin air filter. A clogged air filter reduces air flow and reduces how effective the AC can be. You may also want to charge the system but don't overlook the little stuff.

 

[Old Dogger]

So your MAX cooling will bump up the fan to high and set the mode to recirculate to get you the maximum amount of cooling from your system.

 

[roaniecowpony]

Thanks for all the replies. I found out what everyone stated by driving it and trying it.

Can I trouble some of you to toss a thermometer in your center driver side vent and run your system on Max next time you drive it and post the temperatures here? I can't get below 44-46F. My truck and my wife's car (both R134a systems) get noticeably colder.

 

[NWJeepr]

Thanks for all the replies. I found out what everyone stated by driving it and trying it.

Can I trouble some of you to toss a thermometer in your center driver side vent and run your system on Max next time you drive it and post the temperatures here? I can't get below 44-46F. My truck and my wife's car (both R134a systems) get noticeably colder.

Sounds like you might already know this, but "output" of the AC system will vary with ambient/outdoor temp and airflow over the condenser.

There may be a check procedure and exact spec in the factory service manual, if someone can grab that section for you. I don't know how R1234YF compares in specific conditions, but hopefully someone else does.

 

[roaniecowpony]

Sounds like you might already know this, but "output" of the AC system will vary with ambient/outdoor temp and airflow over the condenser.

There may be a check procedure and exact spec in the factory service manual, if someone can grab that section for you. I don't know how R1234YF compares in specific conditions, but hopefully someone else does.

I do know the ac system performance will vary with ambient conditions. However, my vent temperature seems pretty steady regardless of ambient conditions. My stated vent temps were going down the highway around 60-70mph at 80f, 60% humidity.

 

[roaniecowpony]

AC systems seem to compensate for ambient temperature somewhat, since as the ambient temperature goes up, the high side pressures go up and provide additional cooling upon expansion.

 

[Gorilla57]

I can't get below 44-46F. My truck and my wife's car (both R134a systems) get noticeably colder.

That's the temps I see out of that vent.

 

[mwilk012]

Should be colder but regardless, you need to evacuate the system fully to remove trapped air.

 

[Wabujitsu]

I have zero issues at mid-90s, 60-70% humidity in our two JLU Wranglers, one with a hardtop, the other SOT. Have you checked your cabin air temp?

 

[GATORB8]

Sounds like you might already know this, but "output" of the AC system will vary with ambient/outdoor temp and airflow over the condenser.

There may be a check procedure and exact spec in the factory service manual, if someone can grab that section for you. I don't know how R1234YF compares in specific conditions, but hopefully someone else does.

FSM test temps.

 

[roaniecowpony]

FSM test temps.

Hmm. It appears that I'm inside specification. Still, itd be helpful to know some actual temps to see if what i would like is practical.

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