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Go Back JeepForum.com > Models > Jeep Cherokee & Comanche Forums > XJ Cherokee Technical Forum > whats up with my heater

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Unread 12-13-2013, 07:11 PM   #1
Registered User
2001 XJ Cherokee 
Join Date: Nov 2013
Location: tooele, ut.
Posts: 13
whats up with my heater

My heater doesn't switch to different locations of air for a min or 2 and it doesn't blow hot air. It blows kinda warm air

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Unread 12-13-2013, 09:11 PM   #2
AZ Jeff
Web Wheeler
2014 JK Wrangler 
Join Date: Sep 2005
Location: San Tan Valley Arizona, AZ
Posts: 7,381
There are two separate control systems invovled here.

The "different locations" are your "MODE SELECT" functions controlled by the center knob on the heater control panel. Those are all vacuum operated, and are not instantaneous upon moving selector knob (may take 1-2 seconds to react).

The TEMPERATURE control is an electric stepper motor connected to the shaft on the bottom of the "Blend door" on the heater box. This motor is located on the heater box directly above the transmission tunnel. It can be remove without touching anything else and confirmed to function. If it is OK, then the blend door itself is jammed/broken and requires the heater box to be removed to correct the issue.
1992 XJ -- stock (RIP)
2000 XJ -- lots of basic mods. Sold to fellow forum member. I miss it.
2014 JK -- the project is just starting!
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Unread 12-14-2013, 01:14 AM   #3
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1999 XJ Cherokee 
Join Date: Dec 2011
Location: Kingston, ON
Posts: 306
^^ Spot on

The directionality is most likely the result of weak vacuum. Check for vacuum leaks under the hood.
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