Best place to get 12v

Looking for the best place to get 12v. Need to use one that only has voltage when the truck is on. Just trying not to tap (splice) into a wire to feed it. I saw something on the forum once but now I can’t find it. Thanks.

 

always good to start at battery with 10=12 gauge

use a Centech or similar device

reason being IF there are electrical issues

a trip to a dealer....................simply disconnect eliminating mods/accessories

 

What my friend is trying to say is, add a fuse could be the right choice for you. Where do u need power (inside vs outside cab) and what're u trying to power?

 

Use a voltmeter to determine which fuses have voltage only with the key on, remove that fuse, install an add-a-fuse in that location and wire your accessory up from there. I would look in the interior fuse box first.

 

It’s for a pressure switch for a air tank. Reason I’m wanting the 12v only when the truck is on is so it doesn’t cut on at some random time when the pressure gets low and run the battery down.

 

I know nothing about running on board air, assuming the sensor is only a input and not handling high amperage then the add-a-fuse will work perfect.
Make sure the add-a-fuse you buy is the right style for the fuse your removing, there's at least 4 common types of fuses now, I dont know which 3rd gens use

 

How many amps are you drawing?

 

The solenoid switch itself is just fed by a 12v trigger wire. The compressor itself can pull up to 19 amps but it has its own heavy gauge wire that goes straight to the battery.