Add-a-circuit for hardwiring a gadget?

[cwhitt88]

I've got a 2003 Sport Trac that I bought used, and therefore don't have the manual or diagrams for it.
As well, I'm out of town and can't physically go look at it right now, so I need some info!

I want to "hardwire" my radar detector so that it powers on and off based upon the ignition.

Someone suggested to me that I buy a hardwire kit for it, but then wire it to an existing circuit using this product:
http://www.radarbusters.com/radar-detector-accessories/other-accessories/addacircuit.cfm

1) Will this work? If so, which circuit should I wire into so that the power will be based upon the key being turned to on (even if engine is not necessarily started)?

2) Which type of Add-A-Circuit do I need for a '03 Sport Trac? The Maxi (ATO) fuse, or the Mini (ATM) fuse?

Thanks a ton!!

 

[briwayjones]

I would probably skip that and just tap into an accessory wire for instance like the one for the radio that powers on when you turn on the ignition.

 

[cwhitt88]

Thanks for the reply. So you think I'd be better off just using the little splitter included with this:
http://www.radarbusters.com/radar-detector-accessories/cords/directwirecord.cfm

??