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Jeep Wrangler AC/Heat Problems

11 messages,  Last post on Jul 24, 2012 at 7:45 PM

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Messages Page 2 of 2

#2 of 11 Re: Problem with AC/Heat [paperv2] by mac24

Aug 02, 2011 (6:04 pm)

Replying to: paperv2 (Aug 02, 2011 10:28 am)
The lower speeds of the blower are controlled by a resistor pack which can be found in the passenger foorwell area of the hVAC housing.
 
It's likely that this has burned out and needs replacing.
Other less likely causes are a bad control switch, or issues with the wiring and connectors.

#3 of 11 Re: Problem with AC/Heat [mac24] by paperv2

Aug 03, 2011 (7:57 am)

Replying to: mac24 (Aug 02, 2011 6:04 pm)
I changed the blower motor resistor today. It worked great for about 3 minutes, and then shut off. The blower motor resistor was very hot to touch. Do you think that the part may have been defective, or is there a wiring issue?

#4 of 11 Re: Problem with AC/Heat [paperv2] by mac24

Aug 03, 2011 (6:22 pm)

Replying to: paperv2 (Aug 03, 2011 7:57 am)
The resistor pack is designed to get hot. It works by using some of the power going to the blower motor thus slowing it down, and in doing so the resistor gets hot.
 
As the blower runs without blowing any fuses on 'high' it would appear to be ok.
You need to check the switch, wiring and connectors on the lower speed circuits. Check the appropriate fuses too.

#5 of 11 A/C only comes out of windshield defroster by wink53

Aug 09, 2011 (2:19 pm)

When I turn on my a/c or heater, no matter what position the selector is in, it comes out of the windshield defroster. It turns off when the selector is in the off position so I know the knob isn't set up wrong. Also, every once in a while, it comes out of the defroster and the floor vents at the same time.

#6 of 11 Re: A/C only comes out of windshield defroster [wink53] by mac24

Aug 09, 2011 (2:59 pm)

Replying to: wink53 (Aug 09, 2011 2:19 pm)
As you chose not to post the year of your Wrangler I can only give the generic reply.
The issue is with the diverter doors in the HVAC housing, which depending on the year may be manually controlled, or more likely operated by vacuum actuators.
If vacuum operated then the problem could either be a vacuum leak, faulty actuator(s), or a bad control switch (which controls both vacuum and electrics).
It's also possible that the doors are physically damaged, which was quite common on some years as the doors and linkages were made from a very brittle plastic.

#7 of 11 Re: A/C only comes out of windshield defroster [mac24] by wink53

Aug 10, 2011 (1:27 pm)

Replying to: mac24 (Aug 09, 2011 2:59 pm)
My apologies. My Jeep is a 2002

#8 of 11 Re: A/C only comes out of windshield defroster [wink53] by mac24

Aug 10, 2011 (3:22 pm)

Replying to: wink53 (Aug 10, 2011 1:27 pm)
My apologies. My Jeep is a 2002
 
Vacuum controlled in that case.
 
You can see the actuators move if you get your head into the footwells while someone operates the control knob.
 
If all the actuators work then the problem is damage to the doors or linkage inside the HVAC housing. Fairly big job to dismantle.
 
If some of the actuators work, then either some have failed or there's a problem with their vacuum feeds. Fairly easy to trace.
 
If none of them work, it's likely to be a major vacuum leak. Simple, start at the inlet manifold and follow the hoses until you find the leak.

#9 of 11 97 Jeep Wrangler little heat at floor vents by hikerguy64

Dec 21, 2011 (6:40 pm)

97 Jeep Wrangler Sport.
 
When selecting floor level vents for heat, I notice only a little air coming out of the floor vents, with some air exiting at the defrost and demisters as well. Does not noticeably change when fan speed is increased. If panel or defrost vents are are selected there is noticeable strong air flow.
 
Does this sound like a floor door or actuator problem or is this normal operation.
 
Just had the upper fan box replaced to repair the bad mixing door. Dealer is now saying this air flow pattern is normal. I certainly does not feel normal when more air exits high when the floor vents are selected.

#10 of 11 Re: 97 Jeep Wrangler little heat at floor vents [hikerguy64] by mac24

Dec 22, 2011 (10:49 pm)

Replying to: hikerguy64 (Dec 21, 2011 6:40 pm)
The airflow at floor level is usually perceived as less powerful that that at face or screen level.
The vents are small compared to those on the dash, and unlike your face and hands, your feet and legs are usually covered.
 
However, if only the floor vents are selected then there should be little to no air coming from the face and screen vents.
 
With a little contortion you can watch the actuators move the doors as you operate the sliders on the HVAC control panel.
 
If an actuator functions but the door doesn't move, check the linkage between the two.
If the actuator doesn't function, look first for a vacuum leak.

#11 of 11 A/C problem, TJ 2002 by tjjeep1

Jul 24, 2012 (7:45 pm)

My top vents blow cold air, but my bottom vents blow warm/hot air.

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