# Electrical Problems on a Mazda

**URL:** <https://community.cartalk.com/t/electrical-problems-on-a-mazda/82597>\
**Category:** Maintenance/Repairs\
**Tags:** mazda\
**Created:** [December 9, 2013, 8:01pm UTC](https://community.cartalk.com/t/electrical-problems-on-a-mazda/82597 "2013-12-09T20:01:22Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![The\_Ignorant\_Profess](https://avatars.discourse-cdn.com/v4/letter/t/b5ac83/32.png) [@The\_Ignorant\_Profess](https://community.cartalk.com/u/The_Ignorant_Profess)\
**Post date:** [December 9, 2013, 8:01pm UTC](https://community.cartalk.com/t/electrical-problems-on-a-mazda/82597/1 "2013-12-09T20:01:22Z")

</div>

Well, I took my car (2009 Mazda 3 GT, Auto) to a highly reviewed shop nearby to have some routine maintenance done. They replaced the brakes (new rotors) in front, did a transmission flush, new air filters and an oil change. When I picked up the car, I noticed the car door ajar light was on even after I repeatedly assured myself that every door was latched tight. Also, the auto headlights no longer worked and the power lock on the doors did not work. I told the technician right away, and he said that they are probably just frozen (note: this visit to my local mechanic coincided with a fierce arctic blast and the temperatures have barely climbed above zero in the last 4 days). If things didn’t change the next day, I should contact them. Well the next day I needed a jump from my neighbor. I thought perhaps the door ajar light was a slow drain on the battery, but then I couldn’t start the car just three hours later. So, I went ahead and got a new battery, as mine was four years old and a gas station nearby had Interstate Batteries on sale for $69. I had hoped that connecting a new battery would reset the electrical system and fix the other problems, but no.

Any thoughts on what could be causing this? Should I never trust this mechanic again?

---

<div class="post-metadata">

**Author:** ![BustedKnuckles](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/bustedknuckles/32/25_2.png) [@BustedKnuckles](https://community.cartalk.com/u/BustedKnuckles)\
**Post date:** [December 10, 2013, 1:35am UTC](https://community.cartalk.com/t/electrical-problems-on-a-mazda/82597/2 "2013-12-10T01:35:48Z")

</div>

With the heavily computerized cars we have today, a problem like this may require a visit to the dealer. I am just assuming, but it sounds like you have a failure in the convenience module, although each car maker tends to call it by a different name, and it may require specialized equipment to determine that. This equipment I know the dealer should have, but most independent shops may not. These modules are supposed to control the auto-headlight system, courtesy lights and door sensors, and other functions. A bad module can drain a battery. A simple mistake, like a voltage spike during a jumpstart, can damage these modules.

---

<div class="post-metadata">

**Author:** ![The\_Ignorant\_Profess](https://avatars.discourse-cdn.com/v4/letter/t/b5ac83/32.png) [@The\_Ignorant\_Profess](https://community.cartalk.com/u/The_Ignorant_Profess)\
**Post date:** [December 11, 2013, 5:15am UTC](https://community.cartalk.com/t/electrical-problems-on-a-mazda/82597/3 "2013-12-11T05:15:30Z")

</div>

Thanks for the help. For the time being, it seems to have resolved itself.