# Rattling sound when I turn off my heat or AC fan **URL:** \ **Category:** Maintenance/Repairs\ **Created:** [November 20, 2019, 8:07pm UTC](https://community.cartalk.com/t/rattling-sound-when-i-turn-off-my-heat-or-ac-fan/153210 "2019-11-20T20:07:29Z")\ **Posts on this page:** 11\ **Page:** 1
**Author:** ![Blakensnake](https://avatars.discourse-cdn.com/v4/letter/b/6bbea6/32.png) [@Blakensnake](https://community.cartalk.com/u/Blakensnake)\ **Post date:** [November 20, 2019, 8:07pm UTC](https://community.cartalk.com/t/rattling-sound-when-i-turn-off-my-heat-or-ac-fan/153210/1 "2019-11-20T20:07:29Z")
When my fan speed is at 0 or off there’s a rattle on my car immediately when I turn it on it’ll stop. Could this be a loose heat shield or something ---
**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:** [November 21, 2019, 3:32am UTC](https://community.cartalk.com/t/rattling-sound-when-i-turn-off-my-heat-or-ac-fan/153210/2 "2019-11-21T03:32:33Z")
That sounds more like a faulty hvac door actuator to me. GM product? ---
**Author:** ![Blakensnake](https://avatars.discourse-cdn.com/v4/letter/b/6bbea6/32.png) [@Blakensnake](https://community.cartalk.com/u/Blakensnake)\ **Post date:** [November 23, 2019, 6:08pm UTC](https://community.cartalk.com/t/rattling-sound-when-i-turn-off-my-heat-or-ac-fan/153210/3 "2019-11-23T18:08:28Z")
Yes Toyota / GM made car. Would a video help with sound pinpoint better ---
**Author:** ![COROLLAGUY1](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/corollaguy1/32/7575_2.png) [@COROLLAGUY1](https://community.cartalk.com/u/COROLLAGUY1)\ **Post date:** [November 23, 2019, 8:36pm UTC](https://community.cartalk.com/t/rattling-sound-when-i-turn-off-my-heat-or-ac-fan/153210/4 "2019-11-23T20:36:21Z")
Sure it will! Is this a Chevy Prizm you are talking about? Same as Corolla but a little cheapely made. ---
**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:** [November 23, 2019, 11:11pm UTC](https://community.cartalk.com/t/rattling-sound-when-i-turn-off-my-heat-or-ac-fan/153210/5 "2019-11-23T23:11:15Z")
Suggest to post make/model/year/engine/transmission ---
**Author:** ![Blakensnake](https://avatars.discourse-cdn.com/v4/letter/b/6bbea6/32.png) [@Blakensnake](https://community.cartalk.com/u/Blakensnake)\ **Post date:** [November 25, 2019, 4:13am UTC](https://community.cartalk.com/t/rattling-sound-when-i-turn-off-my-heat-or-ac-fan/153210/6 "2019-11-25T04:13:01Z")
Chevy prizm 2002 1.8 [L] Toyota 1ZZ-FE ---
**Author:** ![jdmere](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/jdmere/32/3002_2.png) [@jdmere](https://community.cartalk.com/u/jdmere)\ **Post date:** [November 25, 2019, 9:48am UTC](https://community.cartalk.com/t/rattling-sound-when-i-turn-off-my-heat-or-ac-fan/153210/7 "2019-11-25T09:48:52Z")
If this only starts when the fan is turned on then I would suspect something that is actually in the fan motor cage that may be bouncing around. I had that happen with a mouse that was in there once. Not hard to pull and take a look. Something like a heat shield would make noise even with the fan off. ---
**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:** [November 26, 2019, 2:58am UTC](https://community.cartalk.com/t/rattling-sound-when-i-turn-off-my-heat-or-ac-fan/153210/8 "2019-11-26T02:58:05Z")
> [@Blakensnake](#): > > [hvac] fan … off there’s a rattle … when I turn [presumably the fan] on [the rattle will] stop. Could this be a loose heat shield or something The hvac fan-speed isn’t related to the exhaust head shield. Heat shields are a common rattle source though. One idea, when you turn the fan on it makes enough noise you can no longer hear the heat-shield rattle. Ask your shop to put your car on a lift & verify the heat shield is solidly attached. ---
**Author:** ![Blakensnake](https://avatars.discourse-cdn.com/v4/letter/b/6bbea6/32.png) [@Blakensnake](https://community.cartalk.com/u/Blakensnake)\ **Post date:** [November 30, 2019, 7:57am UTC](https://community.cartalk.com/t/rattling-sound-when-i-turn-off-my-heat-or-ac-fan/153210/9 "2019-11-30T07:57:48Z")
No once I turn my fans OFF a metal rattling under the passenger front tire starts. Once I turn the heater/air ON it will NOT rattle at all. It’ll stop if fans are going. ---
**Author:** ![kurtwm1](https://avatars.discourse-cdn.com/v4/letter/k/13edae/32.png) [@kurtwm1](https://community.cartalk.com/u/kurtwm1)\ **Post date:** [November 30, 2019, 4:00pm UTC](https://community.cartalk.com/t/rattling-sound-when-i-turn-off-my-heat-or-ac-fan/153210/10 "2019-11-30T16:00:37Z")
Does it do that while stopped and idling and/or while driving? Is it possible that the blower motor drowns out the sound of the rattling when running? ---
**Author:** ![Blakensnake](https://avatars.discourse-cdn.com/v4/letter/b/6bbea6/32.png) [@Blakensnake](https://community.cartalk.com/u/Blakensnake)\ **Post date:** [November 30, 2019, 4:52pm UTC](https://community.cartalk.com/t/rattling-sound-when-i-turn-off-my-heat-or-ac-fan/153210/11 "2019-11-30T16:52:01Z")
Once the fan is OFF it’ll rattle in drive/Idle etc Once fan is on it’ll stop even in idle I mean yeah blower motor could be it because it’s clear this is a fan related problem of some sort