# Mercedes A/C Problem

**URL:** <https://community.cartalk.com/t/mercedes-a-c-problem/3440>\
**Category:** Maintenance/Repairs\
**Tags:** intermittent, airconditioning, engines\
**Created:** [August 21, 2007, 6:04pm UTC](https://community.cartalk.com/t/mercedes-a-c-problem/3440 "2007-08-21T18:04:21Z")\
**Posts on this page:** 7\
**Page:** 1

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**Author:** ![rfelice](https://avatars.discourse-cdn.com/v4/letter/r/0ea827/32.png) [@rfelice](https://community.cartalk.com/u/rfelice)\
**Post date:** [August 21, 2007, 6:04pm UTC](https://community.cartalk.com/t/mercedes-a-c-problem/3440/1 "2007-08-21T18:04:21Z")

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My 2002 E320 has an intermittent A/C problem that relates to engine RPM/torque requirements. At idle or when cruising under low torque conditions, the A/C works fine. However when accelerating or going up hills, the blower fan stops working.

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**Author:** ![Joseph\_E\_Meehan](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/joseph_e_meehan/32/21_2.png) [@Joseph\_E\_Meehan](https://community.cartalk.com/u/Joseph_E_Meehan)\
**Post date:** [August 21, 2007, 6:38pm UTC](https://community.cartalk.com/t/mercedes-a-c-problem/3440/2 "2007-08-21T18:38:53Z")

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Are you sure the fan stops working? Could it be that the vents close?

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**Author:** ![Big\_Riviera\_1990](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/big_riviera_1990/32/43_2.png) [@Big\_Riviera\_1990](https://community.cartalk.com/u/Big_Riviera_1990)\
**Post date:** [August 22, 2007, 12:49am UTC](https://community.cartalk.com/t/mercedes-a-c-problem/3440/3 "2007-08-22T00:49:30Z")

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It’s more likely that the vents are changing position, and the recirc door may be closing too. This would indicate a vacuum leak somewhere in the engine or the HVAC system, or a faulty check valve between the engine and the HVAC, in the vacuum line.

-Matt

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**Author:** ![rfelice](https://avatars.discourse-cdn.com/v4/letter/r/0ea827/32.png) [@rfelice](https://community.cartalk.com/u/rfelice)\
**Post date:** [August 22, 2007, 3:17pm UTC](https://community.cartalk.com/t/mercedes-a-c-problem/3440/4 "2007-08-22T15:17:19Z")

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Yes you are right, the vents change their position as well. The Blower’s RPM’s may drop because of the vent closure. Still don’t know why! Thanks

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**Author:** ![rfelice](https://avatars.discourse-cdn.com/v4/letter/r/0ea827/32.png) [@rfelice](https://community.cartalk.com/u/rfelice)\
**Post date:** [August 22, 2007, 3:21pm UTC](https://community.cartalk.com/t/mercedes-a-c-problem/3440/5 "2007-08-22T15:21:18Z")

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Hey Thanks Matt, I will look in to it.

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**Author:** ![MrPhil](https://avatars.discourse-cdn.com/v4/letter/m/ecccb3/32.png) [@MrPhil](https://community.cartalk.com/u/MrPhil)\
**Post date:** [August 22, 2007, 7:52pm UTC](https://community.cartalk.com/t/mercedes-a-c-problem/3440/6 "2007-08-22T19:52:35Z")

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Something to keep in mind is that on most cars, the A/C compressor will disengage while there is a high power demand on the engine (accelerating, going uphill). I suppose that the whole system could turn off to avoid blowing hot air on the passengers, but your posting seems to indicate that this is a recent problem. As others have suggested, the first place to look is for a vacuum leak that is causing various doors to shut.

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**Author:** ![Craig58](https://avatars.discourse-cdn.com/v4/letter/c/3da27b/32.png) [@Craig58](https://community.cartalk.com/u/Craig58)\
**Post date:** [August 22, 2007, 10:13pm UTC](https://community.cartalk.com/t/mercedes-a-c-problem/3440/7 "2007-08-22T22:13:22Z")

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Try these guys, there are a few folks here who really know these systems:

[http://www.mercedesshop.com/shopforum/forumdisplay.php?f=1](http://www.mercedesshop.com/shopforum/forumdisplay.php?f=1)