The "part-time" indicator light illuminates when the vehicle's transmission is positioned into the 4 wheel drive status. Once the vehicle is returned to 2 wheel drive the front hub locks disengage and the indicator light goes out.
Usually the vin number is in the upper left-hand corner of the dash-board near the corner of the windshield.
On the dash board, just left of the steering column. There are three switches on a raised portion of the dash...the upper one controls the normal lights and the night vision lights, the lower left switch controls the dash lights and the lower right switch is a lock out switch that has to be held while turning the upper light switch on.
Under Left Side Dash Board Under plastic cover .....:)
It is in your house on the upper left corner ...
To the left of the steering column on the dash board
under left side of dash board. Usually in a fuse box
it should be in the lower left hand corner or upper left hand corner
Its located where your left foot would be if you were driving ( upper left corner under the dash).
The make and model would help.
There is a button on the left side by the radio.
under L/S dash upper left side corner
If your 91 park avenue is like the one I have. To the left of the radio is an air duct. To the left of the air duct is the adaptive lamp monitor module. The module is near the top inside of dash.