# 1999 323i Aux Fan Issue - Technical answers needed

**URL:** <https://forums.speedlife.net/t/1999-323i-aux-fan-issue-technical-answers-needed/253315>\
**Category:** Shift518 Automotive\
**Created:** [July 17, 2010, 2:00pm UTC](https://forums.speedlife.net/t/1999-323i-aux-fan-issue-technical-answers-needed/253315 "2010-07-17T14:00:41Z")\
**Posts on this page:** 1\
**Showing post:** 24

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**Author:** ![ninety1two40](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/ninety1two40/32/6332_2.png) [@ninety1two40](https://forums.speedlife.net/u/ninety1two40)\
**Post date:** [July 24, 2010, 5:43pm UTC](https://forums.speedlife.net/t/1999-323i-aux-fan-issue-technical-answers-needed/253315/24 "2010-07-24T17:43:06Z")

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> [@FS: 2003 R1](https://forums.speedlife.net/t/fs-2003-r1/33666/11):
>
> Right on, good observation. I foud out in a few different steps. I checked the wire for continuity/resistance and then checked the operation of the fan control pulse at the pin directly on the DME. What I got was a whole lot of nothing exceptfor a very small amount of voltage, which could be back feeding through the circuit. That’s what I Think is happening.

If you are trying to measure a PWM signal it will only be a 1-3V on a regular multimeter.

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