^^^^^ Good thinking
Didn't even think of the previous owner installing a TOD On/Off switch.
Do the lights move up and down when slipping in AWD mode? If not, that could be your simple fix.
Edit: Wait MattLewis your TOD lights actually do light up when slipping? Then I guess you will have to check under the seat. My TOD ON/OFF switch sends me a "Check TOD" Light I thought the resistor just got rid of the check light not actually make it look as if TOD was working.