relay question (toggle switch)

When running a toggle switch to the relay what constent hot wire do you splice into? I am trying to find a hot under my dash somewhere to splice into this way i can run a toggle switch to my relay to control when the compressor turns off and on. I have a pressure switch but want the constent hot incase my truck is sitting and i want to kick on the compressor. Any ideas? I am in the process of getting everything wired for my truck so i can lay the front next week. I have my tank mounted in back under my bed.. You cant see it from behind the truck.. its pretty slick!!

I spliced mine on to the power antenea wire coming out of my radio, that way when i want to turn my comp off, i just shut off my radio.

this is in combination with a pressure switch though, so it was just for times when the comp was too loud (like drive thrus, or while i was on the cell phone ect ect)

yeah i had considered that too but i want to be able to power the compressor with the truck off

i wouldnt run your compressor with the truck off. if voltage gets low, they go bad. they need the current they ask for. you can run off your battery directly really, and just fuse it with a small AGU fuse or something. Mine is clipped into a wire under the dash for ignition i think it is. i can turn it on and off with the truck off but i really don't like it like this. if i forget it, and just so happen to have a leak, with the switch up i start running my battery down....it hasn't happened yet but i dont like the setup 100%.

i say run it off something you only get power with the truck on....

I keep my toggle attached to an Ignition ON source. I don't want ti running when the truck is off and draining the battery.

I had my compressors run when the truck was off, and it was a nightmare. My battery always died. I finally wired it to my ignition.....kinda like what Seth said, and it hasn't died yet. I also threw in a nitrogen tank, so my compressors don't hardly work at all anyways.....only when I run out nitrogen.

Don't tie your compressors into another supply. Run a stand alone feed,fused. You can use a distribution block, works well.

Mines right off the battery in a clean bundle with the other wires

As stated,don't tie into another feed. Compress draw 30aps ea. in most cases
Avoid a problem & possible fire!!!