# Strange electrical issue

**URL:** <https://community.cartalk.com/t/strange-electrical-issue/56845>\
**Category:** Maintenance/Repairs\
**Tags:** chevrolet, trailblazer\
**Created:** [October 26, 2010, 1:16pm UTC](https://community.cartalk.com/t/strange-electrical-issue/56845 "2010-10-26T13:16:48Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![mlai24](https://avatars.discourse-cdn.com/v4/letter/m/3da27b/32.png) [@mlai24](https://community.cartalk.com/u/mlai24)\
**Post date:** [October 26, 2010, 1:16pm UTC](https://community.cartalk.com/t/strange-electrical-issue/56845/1 "2010-10-26T13:16:48Z")

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I replaced my car battery recently. Now, when I turn on my defroster or air conditioning, the engine stalls out. Scanning tool shows no codes, pulleys o.k. please help!

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**Author:** ![edb1961](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/edb1961/32/122_2.png) [@edb1961](https://community.cartalk.com/u/edb1961)\
**Post date:** [October 26, 2010, 1:33pm UTC](https://community.cartalk.com/t/strange-electrical-issue/56845/2 "2010-10-26T13:33:27Z")

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This thread on another forum should help.

> **[Battery Replacement caused AC problem? - Chevy TrailBlazer, TrailBlazer SS and...](http://forums.trailvoy.com/showthread.php?s=b9f22418fe89188da820bb835f4dd181&t=29256)**
>
> Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum

Not knowing the year or miles on the Trailblazer, I’m assuming it has some miles on it. The jist of the thread is that over time the throttle body gets dirty, the computer compensates for this to keep the truck running normally. When the battery is disconnected for more than 30 minutes the computer settings are lost. When the truck is restarted the default settings are not enough to keep the engine running when the ac is turned on.

Try cleaning the throttle body with throttle body safe cleaner and an old toothbrush. Do not use carb. cleaner as it will damage the coatings on the throttle body and the MAF sensor.

Ed B.

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**Author:** ![lion9car](https://avatars.discourse-cdn.com/v4/letter/l/59ef9b/32.png) [@lion9car](https://community.cartalk.com/u/lion9car)\
**Post date:** [October 26, 2010, 2:55pm UTC](https://community.cartalk.com/t/strange-electrical-issue/56845/3 "2010-10-26T14:55:12Z")

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I suspect your alternator is dying, especially if it had to work overtime when the previous battery was on its last legs. A charging system test would be a good idea here.