I know this is a late post, but I have a solution for those who have this problem in the future... I have a 2000.00 mercury sable ls premium with autolamps that only turned on the parking lights when engaged with no headlights. I went to my ford dealership and bought the following part YF1Z-14A067-AA it's the central fuse/relax box. It doesn't include the GEM module which is connected to the back of this fuse box. But your original one will do fine. It the GEM module has one bolt and 2 clips on each side pop that off and put it on the new fuse box and replace the 6 wiring harasses and you should be good to go. I know it fixed my problem. My central fuse/relay box's "NON"replacable relay went bad therefore it didn't switch on the headlights. There are about 9 "NON" replacable relays in that box which include your autowindow down, your defroster, autolamps, hornstop, and a couple more are in there. So if they also go bad it's time to replace that module. The part listed for $204.00. If you're anything like me you'd get it replaced because the car isn't that old and honestly I've gotten accustomed to the autolamps feature. Cheers and goodluck.
Tony aka mercurysableguy