# 2005 Hyundai Sonata - Horn problem

**URL:** <https://community.cartalk.com/t/2005-hyundai-sonata-horn-problem/175390>\
**Category:** Maintenance/Repairs\
**Tags:** hyundai\
**Created:** [February 23, 2021, 5:54am UTC](https://community.cartalk.com/t/2005-hyundai-sonata-horn-problem/175390 "2021-02-23T05:54:45Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![teddy43](https://avatars.discourse-cdn.com/v4/letter/t/b19c9b/32.png) [@teddy43](https://community.cartalk.com/u/teddy43)\
**Post date:** [February 23, 2021, 5:54am UTC](https://community.cartalk.com/t/2005-hyundai-sonata-horn-problem/175390/1 "2021-02-23T05:54:45Z")

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car had been sitting in driveway for a month when the horn( not the security alarm ) started sounding solid. unhooked the battery and the horns . the doors unlocked during this episode… reset alarm and one month later the battery was down to zero. Obviously have an electrical problem but have no idea where to start

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**Author:** ![tcmichnorth](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tcmichnorth/32/25126_2.png) [@tcmichnorth](https://community.cartalk.com/u/tcmichnorth)\
**Post date:** [February 23, 2021, 4:21pm UTC](https://community.cartalk.com/t/2005-hyundai-sonata-horn-problem/175390/2 "2021-02-23T16:21:14Z")

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First you need to have your battery charged and tested. Replace if necessary. Then it needs to have a parasitic draw test to determine if there’s any unwanted draw from your battery while sitting.

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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:** [February 23, 2021, 4:27pm UTC](https://community.cartalk.com/t/2005-hyundai-sonata-horn-problem/175390/3 "2021-02-23T16:27:06Z")

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That’s a sign that the BCM is starting to fail.

> **[5 Common Symptoms of a Failing Body Control Module (BCM) - Module Experts](https://moduleexperts.com/5-common-symptoms-failing-body-control-module-bcm/)**
>
> If your BCM malfunctions, you will notice a negative effect on the operation of your vehicle. Watch out for these symptoms.

Tester