# A/C needs to learn?

**URL:** <https://community.cartalk.com/t/a-c-needs-to-learn/19597>\
**Category:** Maintenance/Repairs\
**Created:** [September 15, 2008, 2:29pm UTC](https://community.cartalk.com/t/a-c-needs-to-learn/19597 "2008-09-15T14:29:35Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![texases](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/texases/32/862_2.png) [@texases](https://community.cartalk.com/u/texases)\
**Post date:** [September 15, 2008, 2:29pm UTC](https://community.cartalk.com/t/a-c-needs-to-learn/19597/1 "2008-09-15T14:29:35Z")

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Now for my first question - a friend just asked if I’ve ever heard about an A/C system needing to re-learn how to cool after replacing a battery. He just had his 2004 Yukon (with climate control) battery replaced at Sears, and the A/C now blows hot air. The Sears tech told him this was normal, the climate control needed to ‘re-learn’ how to follow the temp settings. Huh???

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**Author:** ![Ranck](https://avatars.discourse-cdn.com/v4/letter/r/aca169/32.png) [@Ranck](https://community.cartalk.com/u/Ranck)\
**Post date:** [September 15, 2008, 3:55pm UTC](https://community.cartalk.com/t/a-c-needs-to-learn/19597/2 "2008-09-15T15:55:17Z")

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That sounds like a know-nothing tech trying to duck liability. He probably blew a fuse or fusible link while changing the battery.

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**Author:** ![TwinTurbo](https://avatars.discourse-cdn.com/v4/letter/t/8baadc/32.png) [@TwinTurbo](https://community.cartalk.com/u/TwinTurbo)\
**Post date:** [September 15, 2008, 4:36pm UTC](https://community.cartalk.com/t/a-c-needs-to-learn/19597/3 "2008-09-15T16:36:44Z")

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On many GMs, the blend door actuator has to be calibrated. When you disconnect the battery long enough, the calibration is lost and must be re-learned. Some models require a scan tool to start the process but I believe your Yukon can do it automatically. Turn all A/C controls off. Disconnect the battery for 2 minutes. Reconnect the battery and start the engine. Do not touch any A/C controls for 2 minutes. The system will exercise the blend door, running it between stops and this will complete the re-calibration. If it still blows hot air, then you have a different problem.

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**Author:** ![texases](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/texases/32/862_2.png) [@texases](https://community.cartalk.com/u/texases)\
**Post date:** [September 15, 2008, 4:39pm UTC](https://community.cartalk.com/t/a-c-needs-to-learn/19597/4 "2008-09-15T16:39:06Z")

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Thanks TT, I’ll let him know.