# Vacuum Switch Ports

**URL:** <https://community.cartalk.com/t/vacuum-switch-ports/100790>\
**Category:** Maintenance/Repairs\
**Tags:** chevrolet, s-10\
**Created:** [March 5, 2017, 2:52am UTC](https://community.cartalk.com/t/vacuum-switch-ports/100790 "2017-03-05T02:52:09Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Mike123](https://avatars.discourse-cdn.com/v4/letter/m/ecc23a/32.png) [@Mike123](https://community.cartalk.com/u/Mike123)\
**Post date:** [March 5, 2017, 2:52am UTC](https://community.cartalk.com/t/vacuum-switch-ports/100790/1 "2017-03-05T02:52:09Z")

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I am working on a 1991 Chevrolet S10.  
It has a thermal vacuum switch for the charcoal canister.  
I just noticed that the “E” port of the switch is connected to the canister, and the “C” port is connected to the intake.  
I believe it should be the other way around. Or does it make a difference?

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**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:** [March 5, 2017, 3:32am UTC](https://community.cartalk.com/t/vacuum-switch-ports/100790/2 "2017-03-05T03:32:57Z")

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If you look under the hood, there should be an emissions sticker that shows the routing of the vacuum hoses.

Tester

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**Author:** ![pleasedodgevan2](https://avatars.discourse-cdn.com/v4/letter/p/ad7895/32.png) [@pleasedodgevan2](https://community.cartalk.com/u/pleasedodgevan2)\
**Post date:** [March 5, 2017, 5:06am UTC](https://community.cartalk.com/t/vacuum-switch-ports/100790/3 "2017-03-05T05:06:38Z")

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It may not make a difference even if the lines are on the wrong way.