In a new Ford F350 SD where is the closest switched power line to the rearview mirror? At the fuse panel by the passengers feet? In the roof lining? Trying to hard wire a radar detector that mounts to windshield by the mirror. Thanks.

 

There is a Yellow with green stripe wire that goes to the center interior lamp assembly that you could use. It is not switched but is controlled by the battery saver relay. It would keep power on the radar detector until the interior lights shut off by the battery saver relay circuit.

You can also use the Green with violet stripe wire if you have a moon roof or the wire is there in the harness.

You could run a wire up the driver side A pillar from the battery junction box under the hood, Fuse 32. It hot in the start and run position.

 

Cool, could I just tap into it as it enters the Driver side foot well, or up the post as it must run the interior lamps by the rearview mirror right?

 

Checked it out and only found the yellow wire which didn't work it. So I ran it down the passenger side and hooked into the internal fuse panel. All is good now.

 

lonewolftx... this should be a no brainer but I am trying to tap into the internal fuse panel at the radio fuse and I am getting low voltage on the radar.. grounding problem I think BUT I want the fuse tap to be on the fuse that will turn off when the door opens like the radio does.. I am going into #28 on my 2008 F250 but the radar stays on... what did you tap into ?
Thanks for your help.
Chungy

 

I tied into an interior switched fuse at the fuse box in the passenger footwell. I don't think you have the same setup as my 2016.

 

I have an Escort radar detector and it shows a "Low Voltage" message when the auto battery is low when starting up the truck. It works as a volt meter. Is this the message you are getting.