Drop the spare tire and you should see where the harness connects.. At least that's where it was on my 97 F150 and my 13 F150..
I didn't have to change mine, since it came with the tow package that has the 7 pin, but even in 97, all you had to do was get the harness and add a few fuses and a relay or two to make it all work..
The integrated brake controller is nice too... Since you don't have the 7 pin, doubt you have the IBC, but it's a nice feature for sure!
Good luck!
Mitch
2013 F150 XLT 4x4 SuperCab Max Tow Egoboost 3.73 gears #7700 GVWR #1920 payload. 2019 Rockwood Mini Lite 2511S.