[40cpe]

You want the feed side of the relay to bypass the ignition switch. The wire to trigger the relay "on" can be fed by the ignition switch, a toggle switch, or a fan thermostat. I would think a thermostat would be preferable, I understand the fans are not designed to run all the time.

I don't have a relay in front of me to tell you the numbers on the terminals to connect to. It should be available on Google if your harness didn't come with a schematic.

If your thermostat monitors radiator temp you might can let it run with ignition off. If it is driven by a sensor on the engine the fan will run a long time before it shuts off.