Shift Lock Button-91 Ls 400

[tytan]

I have a 91 LS 400 and can not find in the manual what this shift lock button is for ??? I have read thru other posts and assume the system won't let you shift unless you have the brake on but how does the button operate?? Any help will be greatly appreciated !!!!

[1990LS400]

The shift lock button is important for at least two reasons: Allows a tow truck operator to straighten the front wheels for towing if he does not have an ignition key. Allows the driver to shift out of park if the brake pedal switch fails. - You will appreciate this if your brake pedal switch fails and you would still like to be able to shift out of park and drive your car. I sure did.