This is from a 97 electrical manual so hope it is the same. The parking lights get power from the tail light relay, which is controlled by the combination headlight switch. That relay feeds 12V to the 15A tail light fuse. See if you have voltage coming into that fuse from the relay. You ought to be able to hear or feel(if you hold a finger on it) the relay kick in when the light switch is turned on. The tail light realy should be in the driver's side kick panel, the upper right relay. There is a start.

1997 T-100 4X4 Xcab,Warn Hubs
02 Camry LE
2008 Yaris