# 2003 pontiac montana minivan heater problem

**URL:** <https://community.cartalk.com/t/2003-pontiac-montana-minivan-heater-problem/20708>\
**Category:** Maintenance/Repairs\
**Created:** [October 14, 2008, 4:32am UTC](https://community.cartalk.com/t/2003-pontiac-montana-minivan-heater-problem/20708 "2008-10-14T04:32:44Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![panther](https://avatars.discourse-cdn.com/v4/letter/p/a698b9/32.png) [@panther](https://community.cartalk.com/u/panther)\
**Post date:** [October 14, 2008, 4:32am UTC](https://community.cartalk.com/t/2003-pontiac-montana-minivan-heater-problem/20708/1 "2008-10-14T04:32:44Z")

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My 2003 pontiac montana minivan will only blow warm air when accelerating. When we come to a stop at a light the air will go cold. Also we do not get any warm air until the temperature gauge has climbed quite a bit. Any ideas as to a fix?

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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:** [October 14, 2008, 10:53am UTC](https://community.cartalk.com/t/2003-pontiac-montana-minivan-heater-problem/20708/2 "2008-10-14T10:53:35Z")

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I suspect a vacuum leak in the HVAC system. The airflow doors, or flaps, within the system are vacuum controlled. When you accelerate there is less engine vacuum and when idling or decelerating there is more. A leak in the system will allow the flaps to move when they shouldn’t, and the symptoms you describe are typical of a vacuum leak.

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**Author:** ![Roadrunner](https://avatars.discourse-cdn.com/v4/letter/r/d2c977/32.png) [@Roadrunner](https://community.cartalk.com/u/Roadrunner)\
**Post date:** [October 14, 2008, 5:34pm UTC](https://community.cartalk.com/t/2003-pontiac-montana-minivan-heater-problem/20708/3 "2008-10-14T17:34:38Z")

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Sorry Mcp, but I respectfully disagree with the point you made referring to vacuum controlled doors.

I have the exact same system in my Olds Silhouette and a couple of months ago I was having problems with cold/warm air direction.

After testing my tech took the dash apart, sure enough, the ELECTRIC door motor was burned out.

The Montana is a sister to the Silhouette.

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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:** [October 14, 2008, 6:19pm UTC](https://community.cartalk.com/t/2003-pontiac-montana-minivan-heater-problem/20708/4 "2008-10-14T18:19:38Z")

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Thanks, Roadrunner. I’ll try to remember in the future. I know some vehicles use vacuum and some are electric, I just can’t keep track of which are which.

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**Author:** ![Roadrunner](https://avatars.discourse-cdn.com/v4/letter/r/d2c977/32.png) [@Roadrunner](https://community.cartalk.com/u/Roadrunner)\
**Post date:** [October 15, 2008, 12:50am UTC](https://community.cartalk.com/t/2003-pontiac-montana-minivan-heater-problem/20708/5 "2008-10-15T00:50:49Z")

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Don’t feel bad, I can’t remember all the info either.