# Ask Someone: 2002 Mercury Grand Marquis - Clicking noise and hot air

**URL:** <https://community.cartalk.com/t/ask-someone-2002-mercury-grand-marquis-clicking-noise-and-hot-air/121653>\
**Category:** Maintenance/Repairs\
**Tags:** mercury\
**Created:** [July 25, 2018, 3:07am UTC](https://community.cartalk.com/t/ask-someone-2002-mercury-grand-marquis-clicking-noise-and-hot-air/121653 "2018-07-25T03:07:36Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![LuisMendez-Chaviano](https://avatars.discourse-cdn.com/v4/letter/l/7ba0ec/32.png) [@LuisMendez-Chaviano](https://community.cartalk.com/u/LuisMendez-Chaviano)\
**Post date:** [July 25, 2018, 3:07am UTC](https://community.cartalk.com/t/ask-someone-2002-mercury-grand-marquis-clicking-noise-and-hot-air/121653/1 "2018-07-25T03:07:36Z")

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clicking noise under dash and hot air.

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**Author:** ![Purebred](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/purebred/32/46796_2.png) [@Purebred](https://community.cartalk.com/u/Purebred)\
**Post date:** [July 25, 2018, 9:41am UTC](https://community.cartalk.com/t/ask-someone-2002-mercury-grand-marquis-clicking-noise-and-hot-air/121653/2 "2018-07-25T09:41:12Z")

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The HVAC system has ‘blend doors’, these control blending the hot and cold air, and the direction of the airflow, I.e. floor, dash, or defrost. The clicking is the actuator for the blend door.  
You could try googling it to see if it is something you wish to try doing yourself. I had mine fixed about 6 months ago but can not recall how much it was.

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**Author:** ![BillRussell](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/billrussell/32/3179_2.png) [@BillRussell](https://community.cartalk.com/u/BillRussell)\
**Post date:** [July 25, 2018, 10:47pm UTC](https://community.cartalk.com/t/ask-someone-2002-mercury-grand-marquis-clicking-noise-and-hot-air/121653/3 "2018-07-25T22:47:15Z")

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The blend doors are usually driven by electric servo motors driving plastic gears. If some of the teeth break off the gear, the motor keeps running trying to get the door into the proper position.

Taking apart a dash to repair these usually is a very expensive operation.

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**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\
**Post date:** [July 25, 2018, 10:53pm UTC](https://community.cartalk.com/t/ask-someone-2002-mercury-grand-marquis-clicking-noise-and-hot-air/121653/4 "2018-07-25T22:53:10Z")

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There are two types of control doors in your HVAC system

These are the blend door and mode doors.

The blend door controls if cold or hot air enters the cabin.

The mode doors control where this cold/hot air comes out of the HVAC system.

There’s a problem with the blend door/actuator.

Tester

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**Author:** ![George\_San\_Jose1](https://avatars.discourse-cdn.com/v4/letter/g/e5b9ba/32.png) [@George\_San\_Jose1](https://community.cartalk.com/u/George_San_Jose1)\
**Post date:** [July 26, 2018, 2:38am UTC](https://community.cartalk.com/t/ask-someone-2002-mercury-grand-marquis-clicking-noise-and-hot-air/121653/5 "2018-07-26T02:38:14Z")

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Concur, probably a problem with a blend door actuator. But ask at a dealership if a blend door homing procedure might be the best first course of action.