# Control Module or what? Jeep 1999 Grand Cherokee

**URL:** <https://community.cartalk.com/t/control-module-or-what-jeep-1999-grand-cherokee/25130>\
**Category:** Maintenance/Repairs\
**Created:** [January 18, 2009, 5:03pm UTC](https://community.cartalk.com/t/control-module-or-what-jeep-1999-grand-cherokee/25130 "2009-01-18T17:03:17Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![richmorgan](https://avatars.discourse-cdn.com/v4/letter/r/3d9bf3/32.png) [@richmorgan](https://community.cartalk.com/u/richmorgan)\
**Post date:** [January 18, 2009, 5:03pm UTC](https://community.cartalk.com/t/control-module-or-what-jeep-1999-grand-cherokee/25130/1 "2009-01-18T17:03:17Z")

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Why???  
  
  
  
 Dash gauges come on and off intermittantly. Dash “idiot” lights come on and off intermittantly. Windows no longer roll down. Controls for radio on steering column no longer work (although cruise control works fine). Headlights no longer work in “Auto” mode although work fine in manual mode.  
  
  
  
 IS this a failure or loss of program of one of the control modules?  
  
  
  
 Also, possibly and unrelated topic; the passenger side heating system provides only cold air.

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**Author:** ![wizard](https://avatars.discourse-cdn.com/v4/letter/w/a87d85/32.png) [@wizard](https://community.cartalk.com/u/wizard)\
**Post date:** [January 18, 2009, 11:00pm UTC](https://community.cartalk.com/t/control-module-or-what-jeep-1999-grand-cherokee/25130/2 "2009-01-18T23:00:58Z")

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What year is this vehicle and how old is the battery?

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**Author:** ![mcparadise](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/mcparadise/32/32_2.png) [@mcparadise](https://community.cartalk.com/u/mcparadise)\
**Post date:** [January 18, 2009, 11:05pm UTC](https://community.cartalk.com/t/control-module-or-what-jeep-1999-grand-cherokee/25130/3 "2009-01-18T23:05:54Z")

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Well, it’s a 1999 according to the headline. We don’t know about the battery yet.

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**Author:** ![wizard](https://avatars.discourse-cdn.com/v4/letter/w/a87d85/32.png) [@wizard](https://community.cartalk.com/u/wizard)\
**Post date:** [January 18, 2009, 11:09pm UTC](https://community.cartalk.com/t/control-module-or-what-jeep-1999-grand-cherokee/25130/4 "2009-01-18T23:09:26Z")

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Most modern cars go crazy when voltage is not up to par. If you find that the battery is about 4 years old, start thinking about a new one.

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**Author:** ![richmorgan](https://avatars.discourse-cdn.com/v4/letter/r/3d9bf3/32.png) [@richmorgan](https://community.cartalk.com/u/richmorgan)\
**Post date:** [January 19, 2009, 12:31pm UTC](https://community.cartalk.com/t/control-module-or-what-jeep-1999-grand-cherokee/25130/5 "2009-01-19T12:31:35Z")

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Surprisingly the battery is \<1yr old. Another website posting mentioned something about the BCM (Body Control Module) losing it’s program. Any ideas?

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**Author:** ![Loafer](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/loafer/32/28_2.png) [@Loafer](https://community.cartalk.com/u/Loafer)\
**Post date:** [January 19, 2009, 1:54pm UTC](https://community.cartalk.com/t/control-module-or-what-jeep-1999-grand-cherokee/25130/6 "2009-01-19T13:54:51Z")

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BCM was the problem on our old minivan. If I remember right it’s like a $300.00 part:(