What gets constant 12v under the hood, and is turned off when the engine is off?

[Napoleon_Tanerite]

I'm thinking of setting up some daytime running lights. I'd like to wire it to something that is powered when the engine is running, and de-powered when the engine is off. That was I get away from having to run a manual switch into the cab. Anyone know of anything good I can tap off of and save me hours of ****ing around under the hood with a volt meter?

 

[Warthog]

I think you are out of luck.

All the items to tap power off of are always hot.

battery
12v positive terminal block

The ignition switch controls the switched power to the fuse box.

 

[Napoleon_Tanerite]

i might end up having to wire it to my stereo/accy power switch. I didn't want to run wires to the cab and back, but I will if I must.

 

[Warthog]

The only item that I know of that is "hot" with the engine running is the Injector Pump pink wire.

 

[doghead]

I think the white wire that feeds the wiper motor and also feeds the fuel filter heater(same wire) is switched with the key.

if so, you could use that to power a relay coil to turn on running lights.

 

[merace19]

Just need 1 wire out from the inside. tape in to the accessory fuse and run to a relay under the hood. Use a good constantly energized relay and your good. Relay wiring writes ups all over the internet.

 

[wallew]

I can't remember which wire that I used, but when I add an electric fuel pump, it is connected to a part of the fuse box that comes on ONLY when the ignition switch is ON.