When I got my 2005 LS back in May I was surprised that it didn't have this feature being that the LS is a luxury vehicle. My wife's 2005 Pacifica had it so it was around in 2005. Has anyone added this feature? It seems that the signals are controlled by the FEM and the REM so the adjustable relay I found online won't work. Is there a way to add this feature that isn't too complicated or expensive?