true ignition source

I am installing a battery isolator in a 99 blazer and it requires 1 terminal be connected to a true ignition source where would that be?? thanks dave

If its a low-power circuit (ie, less than 20 amp), such as a relay, you could use a terminal on the fuse block. I find most fuse blocks have a 1 or 2 unused terminals.(if not, you might get a special blade terminal that allows you to tap power off an existing fuse).

Use one that delivers electricity only when the ignition is switched on, but shuts off when the ignition key is turned off.
Be sure to use an in-line fuse that's appropriate for the power load, and run the wire inside plastic conduit, especially if you have to run it through a hole in the fire wall.

thanks for the info,much appreciated.Dave