12v hot ignition wire

[76k5blazerr]

First post on the 67-72 forum. 3 weeks ago I got a 72 c10. The only thing it leaks is tranny fluid so I bought a new pan and a nice thick pan gasket in hopes to stop the leak. Also bought a tranny temp gauge. The temp gauge needs a 12v hot ignition wire to run to one of the terminals on the back of the gauge. So my question is, what is the easiest way to get a hot ignition wire, that only has power when the key is on, to the gauge. Do I splice into a wire or just run one from an accessory fuse port on the fusebox. Also, what's the best way to splice the gauge backlight into the headlights so it comes on when you pull the headlight switch? Thanks y'all. Electrical is not my area of expertise.

 

[ekajkrats]

I would think getting power from inside the cab would be easiest because that is where the gauge is going that needs the power.
See the lower right red wire, that's Ignition Unfused. The yellow wire is the cluster feed:

 

[diesel4me]

You can tap into the fuse box where it says "PNL " near that yellow wire,to feed the gauge light,so it only comes on with the light switch...there might be an empty tab for a male connector in the box at that location..

You'll have to use a test light to find which tap on the fuse box supplies 12V with the key "on" only--be sure its not hot with the key on "acc" too..if there is no unused taps,you may have to splice into an existing wire or use a double spade connector to allow two wires to feed off one tap..