That park light relay is usually in the underhood relay/fuse block near the battery. Which relay is it? Good question.
Even if the relay contacts are no good and you have no park lights whatsoever, you should still hear the relay click when the switch is turned to the ON position. If anything, you could turn on the lights and start pulling relays until you find the one that is on because it will click as you remove it.
As for wire color from the column, even a good wiring diagram has been known to be wrong. I would just use a test light for that and verify that you have what you're looking for when you operate the switch. That would be the best place to start and go from there if you haven't found the problem.
Good luck and hope you find the problem soon!
