cooling fan

I have a 2006 crown vic old police car the fan for the radiator not working any where to start to see what it is thanks

Check the relay/s. See if fan motor is getting power with a voltmeter.

I straight wired it and the fan runs

Still need to test the circuit going to the fan. Then identify the fan or fans power relays and test them. Or you can swap the relay with another identical,(same part number),relay from another circuit in the same relay box temporarily to see if it works.