Sorry, I don't have a link to gen I data to post, but here's what the gen II service manual has on it. I do have the gen II wiring diagrams in print form. They show headlight relays only for the HID option. Ford has been somewhat consistent (on the cars I have dealt with) about just having non-replaceable (unless you have a soldering iron) headlight relays in the FEM or LCM (Lighting Control Module) or GEM, depending on what car you are talking about. In the early 2000s, the LCMs on Crown Vics and Grand Marquis are well known for internal relay failure and PCB soldering issues.
( I should point out that power for the headlights as well as most of the rest of the car is switched by relays in the junction box in the trunk. These relays turn on when you open a door or do most anything else, and turn off 20 minutes after you last disturb the car (if the key is off). If one of these were at fault, you should have far more problems than headlights.)
http://deneau.info/ls/s6x~us~en~file=s6xh1003.htm~gen~ref.htm