Air Conditioning Question
05-28-2013, 03:15 AM
#12
JK Super Freak
Join Date: Jul 2008
Location: Front Royal, Virginia, United States
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05-28-2013, 03:29 PM
#13
JK Newbie
My '08 started doing that at about 25,000 miles. Dealer said normal. AC shop said low voltage situation, changed battery, worked fine until about 40,000 miles and started doing it again recently. The electrical system in these things is so screwy. Sometimes power windows won't work, have to shut down and restart and they'll start working again. Same goes for my power outlets. Hate saying it, "it's a jeep thing", remember when that meant good times, top down, doors off. Has a whole new meaning with the JK's.
05-28-2013, 05:09 PM
#14
JK Enthusiast
Just curious as to whether anyone has experienced something similar to what I am. I have a 13 JKUR that periodically will cycle the A/C output level down from from the setting I have it on to the lowest setting. Within a few seconds it comes back foul strength. It never turns completely off just spools down. I do not have the auto,attic climate control so that's not factoring in to it. Just curious as to whether anyone else was experiencing this. I know if I bring it to the stealership I'll waste a few hours and get the standard "Could not duplicate" response. That and it doesn't actually turn off so I'm not sure I actually have an issue or if its just the compressor or something doing what the widget was designed to do.
When you state the A/C output level cycles down; what does this mean?
Does it mean the air flow decreases or the discharge temperature warms up?
I realize the explanation below is not a solution for the JKs, but I am just using it as an example.
The 97 & 98 XJs had a problem of when the engine was under load; the A/C would appear to stop functioning, but actually the engine vacuum would drop off causing the vents to shift to defrost (default position when vacuum is lost).
The solution was to install a check valve in the vacuum line feeding the climate control system.
Chrysler created a TSB that addressed this problem with this solution.
08-08-2015, 05:21 PM
#15
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Join Date: Jun 2015
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engine vacuum drops off on long acceleration up hill... causing loss of vent flow
On my 2015 Sport 2-door, it appears that the engine vacuum drops off on long acceleration up hill...
This causes ventilation dampers to shift positions and a loss of A/C air flow from the vents...
Charles, you nailed it ! What can we do?
This causes ventilation dampers to shift positions and a loss of A/C air flow from the vents...
Charles, you nailed it ! What can we do?
08-08-2015, 08:52 PM
#16
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My 08' doesn't do this, but my wife's 14' Cherokee dose. I think at has to do with the newer alternators, they are power on demand. The PCM doesn't kick the output up fast enough. So the blower motor slow down. Or it could be a way to keep the evaporator core from freezing up.
Last edited by AC/DC; 08-08-2015 at 08:55 PM.
08-09-2015, 04:32 AM
#17
JK Super Freak
if a 15 is losing vent pressure.. these things use electric actuators.. something else is wrong...
my '13 did the sut on / off thing as well as sometimes my rear defrost light would flash and id get no A/C.. they replaced my HVAC controller and never done either since..
-Christopher
my '13 did the sut on / off thing as well as sometimes my rear defrost light would flash and id get no A/C.. they replaced my HVAC controller and never done either since..
-Christopher