GM Service Manual Online
For 1990-2009 cars only

The courtesy lamps will come on and stay on for a set time whenever you press UNLOCK on the remote keyless entry transmitter.

The lamps will stay on while a door is opened and then turn off automatically about 25 seconds after it is closed. If the UNLOCK button is pressed and a door is not open, the lamps will turn off after about 40 seconds.

Entry lighting includes a feature called theater dimming. With theater dimming, the lamps do not turn off at the end of the delay time. Instead, they slowly dim after the delay time and then turn off.

The courtesy lamps are canceled if the ignition key is turned to RUN or START and will not come on unless a door is opened.