# How would I add a relay to turn on a new device when the car is on?

**URL:** <https://forums.speedlife.net/t/how-would-i-add-a-relay-to-turn-on-a-new-device-when-the-car-is-on/27716>\
**Category:** NYSpeed Automotive\
**Created:** [April 16, 2007, 11:57am UTC](https://forums.speedlife.net/t/how-would-i-add-a-relay-to-turn-on-a-new-device-when-the-car-is-on/27716 "2007-04-16T11:57:32Z")\
**Posts on this page:** 1\
**Showing post:** 6

<div class="post-metadata">

**Author:** ![Freek](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/freek/32/7357_2.png) [@Freek](https://forums.speedlife.net/u/Freek)\
**Post date:** [April 16, 2007, 12:17pm UTC](https://forums.speedlife.net/t/how-would-i-add-a-relay-to-turn-on-a-new-device-when-the-car-is-on/27716/6 "2007-04-16T12:17:38Z")

</div>

the blue wire on the radio harness is the ignition wire.

if that doesn’t work you can tap off the accessory wire at the wiring harness which is blue also.

the 12 volt constant is the red black stripe  
the radio illumination is the red blue stripe

does that help a bit ? 🙂

---

_[View the full topic](https://forums.speedlife.net/t/how-would-i-add-a-relay-to-turn-on-a-new-device-when-the-car-is-on/27716)._