Hi, my name is Ed. Welcome to Just Answer!.
If history repeats itself, you will probably be needing a new Integrated Power Module (IPM), which is your fuse and relay box under the hood. Park lamps are powered from a relay that's turned on electronically by the Front Control Module (FCM) which is mounted on the IPM body, but road salt may have gotten up into the circuit board that connects the FCM to the park lamp relay's control terminal. Without a connection between FCM and the relay, the park lamps can't be turned on.
But let's check the fuse first, just in case. The feed begins with Fuse 15, which is one of those big 50 amp fuses with the clear plastic tops. Both sides of the relay are powered with this fuse, which feeds terminals 85 and 30 in the relay base. You can determine terminal numbering by checking the numbers on the underside of the relay, mentally transferring these locations to the IPM. If you'd like to check the entire output circuit, jump Terminal 30 to 87 in the IPM relay base and it should turn the park lamps on.
If that works, it leaves only a bad relay or failed control circuit to the relay as the problem. You can swap another relay in from any place in the IPM that uses this type of relay... which are many.
The replacement IPM will come without the FCM, which means you'll need to transfer it over. The FCM is the shiny metal box on the driver's side of the IPM unit. All fuses and relays will be included with the new IPM, but you may need to press a fuse or two down to engage systems such as airbag and the Ignition-Off Draw (IOD) relay, both of which may be hidden in plastic fuse carrier-holders.
Check it out and let me know if you have any questions or problems. I'll be glad to help.
Thanks for writing,