# Car revs when shifting with defroster on

**URL:** <https://community.cartalk.com/t/car-revs-when-shifting-with-defroster-on/35595>\
**Category:** Maintenance/Repairs\
**Tags:** neon, dodge\
**Created:** [August 25, 2009, 7:05pm UTC](https://community.cartalk.com/t/car-revs-when-shifting-with-defroster-on/35595 "2009-08-25T19:05:51Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Max\_Power](https://avatars.discourse-cdn.com/v4/letter/m/db5fbb/32.png) [@Max\_Power](https://community.cartalk.com/u/Max_Power)\
**Post date:** [August 25, 2009, 7:05pm UTC](https://community.cartalk.com/t/car-revs-when-shifting-with-defroster-on/35595/1 "2009-08-25T19:05:51Z")

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I have a 1998 Dodge Neon with a 4-cylinder, 5-speed manual transmission. When the defroster is on the engine races when I depress the clutch to change gears. What is causing this?

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**Author:** ![Joseph\_E\_Meehan](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/joseph_e_meehan/32/21_2.png) [@Joseph\_E\_Meehan](https://community.cartalk.com/u/Joseph_E_Meehan)\
**Post date:** [August 25, 2009, 8:01pm UTC](https://community.cartalk.com/t/car-revs-when-shifting-with-defroster-on/35595/2 "2009-08-25T20:01:24Z")

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I am going to take a SWAG. The defroster activates the air conditioner. (it helps dehumidify the air) and the extra power drain from the AC running causes the idle speed to go up.

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**Author:** ![researcher](https://avatars.discourse-cdn.com/v4/letter/r/edb3f5/32.png) [@researcher](https://community.cartalk.com/u/researcher)\
**Post date:** [August 26, 2009, 7:54pm UTC](https://community.cartalk.com/t/car-revs-when-shifting-with-defroster-on/35595/3 "2009-08-26T19:54:28Z")

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Does the engine race when the A/C is ‘on’ and cooling? I assume this car has Air Conditioning. Does the A/C work?

Your answers will help us diagnose.