# AC Stalls Car

**URL:** <https://community.cartalk.com/t/ac-stalls-car/63629>\
**Category:** Maintenance/Repairs\
**Tags:** explorer, ford\
**Created:** [April 12, 2011, 1:49am UTC](https://community.cartalk.com/t/ac-stalls-car/63629 "2011-04-12T01:49:31Z")\
**Posts on this page:** 5\
**Page:** 1

<div class="post-metadata">

**Author:** ![hildephoto](https://avatars.discourse-cdn.com/v4/letter/h/a698b9/32.png) [@hildephoto](https://community.cartalk.com/u/hildephoto)\
**Post date:** [April 12, 2011, 1:49am UTC](https://community.cartalk.com/t/ac-stalls-car/63629/1 "2011-04-12T01:49:31Z")

</div>

When I turn-on AC or defroster, motor idles rough then stalls.  
  
 My mechanic says it is not related to CHECK ENGINE light or exhaust O2 sensor? Any ideas? I have an 02 Ford Explorer.

---

<div class="post-metadata">

**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:** [April 12, 2011, 2:09am UTC](https://community.cartalk.com/t/ac-stalls-car/63629/2 "2011-04-12T02:09:26Z")

</div>

The problem might be with the Idle Air Control valve. This valve adjusts the engine idle depending on the load impossed on the engine at idle. So for example in your case, when the AC is turned on the IAC valve fails to bump the engine idle up to compensate for the load impossed by the AC compressor on the engine. This then causes then engine to idle rough and stall.

Tester

---

<div class="post-metadata">

**Author:** ![kawasaga](https://avatars.discourse-cdn.com/v4/letter/k/2acd7d/32.png) [@kawasaga](https://community.cartalk.com/u/kawasaga)\
**Post date:** [April 12, 2011, 3:30am UTC](https://community.cartalk.com/t/ac-stalls-car/63629/3 "2011-04-12T03:30:56Z")

</div>

Does th AC work? It isn’t out of the question that the AC compressor has fallen to pieces. If it works then, this isn’t the answer.

---

<div class="post-metadata">

**Author:** ![the\_same\_mountainbike](https://avatars.discourse-cdn.com/v4/letter/t/c89c15/32.png) [@the\_same\_mountainbike](https://community.cartalk.com/u/the_same_mountainbike)\
**Post date:** [April 12, 2011, 6:04pm UTC](https://community.cartalk.com/t/ac-stalls-car/63629/4 "2011-04-12T18:04:10Z")

</div>

It’s also possible that the AC compressor is bound up. Usually I’d expect this to snap the belt, but it can stall the engine too.

---

<div class="post-metadata">

**Author:** ![cigroller](https://avatars.discourse-cdn.com/v4/letter/c/c68b51/32.png) [@cigroller](https://community.cartalk.com/u/cigroller)\
**Post date:** [April 12, 2011, 11:05pm UTC](https://community.cartalk.com/t/ac-stalls-car/63629/5 "2011-04-12T23:05:30Z")

</div>

“My mechanic says it is not related to CHECK ENGINE light”

I’m not a mechanic, but I don’t use them any more because I don’t have any I trust. Should I assume from the statement above that your check engine light is on? There’s nothing wrong with the answers so far, but if your check engine light is on then there are error codes stored in the computer. They look like “P1234” - ask your mechanic what they are and report them.