I figured I'd try and look for ya, since I'm already digging through the schematics on my 04 LeSabre FSM, looking for a fix for my heated seats.
Only thing I see right now that is hot in acc or in run, is an orange wire off the ignition switch itself. It runs to the ACCY relay #34 in the underhood fuse block. It shows no connection from the lock position or the unlock position on the switch, which I take it to mean that the DIM (or what actually controls the RAP) isn't directly acting on it.
I could be wrong though, but looks like something you could test to see if it fits what you need it to do.
2004 Buick LeSabre Custom FE5 GXP suspension conversion. 170Kmi
2001 Silverado 4WD 5.3L, 33" BFG ATs, Z71/Z82 pkg, 147kmi.