Hot ignition wire under hood

I installed the tripple threat radiator in my 99 xj and need to find a live wire under the hood that's hot when the ignition is on. I know where to find under the dash but it would be so much easier if I knew where one is under the hood. Any help is deeply cool. Thanks hooked on xjs.

There are a bunch of sources off the PDC(thing with fuses and relays on the passenger side). Shouldn't be too hard to find if you understand how a relay works and you have a multimeter or test light.

There's one from the computer back to the PDC, just put a relay on it and draw battery when the ignition circuit is active.