# Is it ok to short out a control wire from the PCM?

**URL:** <https://community.cartalk.com/t/is-it-ok-to-short-out-a-control-wire-from-the-pcm/19762>\
**Category:** Maintenance/Repairs\
**Tags:** relay, coolant, fans, radiators\
**Created:** [September 19, 2008, 5:05pm UTC](https://community.cartalk.com/t/is-it-ok-to-short-out-a-control-wire-from-the-pcm/19762 "2008-09-19T17:05:09Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![car-stuck](https://avatars.discourse-cdn.com/v4/letter/c/c0e974/32.png) [@car-stuck](https://community.cartalk.com/u/car-stuck)\
**Post date:** [September 19, 2008, 5:05pm UTC](https://community.cartalk.com/t/is-it-ok-to-short-out-a-control-wire-from-the-pcm/19762/1 "2008-09-19T17:05:09Z")

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I’m thinking about putting in a switch to ground from the green/white relay control wire for the Radiator Fan Control Relay as I can’t get the PCM to turn the fan on, even though everything else tests OK, and the fan runs fine once the relay closes.  
  
  
  
 (1993 Chevy Corsica).  
  
  
  
 If I don’t disconnect the control wire from the PCM (power control module), could this damage a component in the PCM?

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**Author:** ![Cougar](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/cougar/32/21348_2.png) [@Cougar](https://community.cartalk.com/u/Cougar)\
**Post date:** [September 19, 2008, 5:52pm UTC](https://community.cartalk.com/t/is-it-ok-to-short-out-a-control-wire-from-the-pcm/19762/2 "2008-09-19T17:52:17Z")

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I posted you an answer to this question in another thread.