Hello, ceiling light does not work even though the light on the door works and the "door open" icon on the dash is on when the door is open, it works only when I flip it to "always on".. any ideas ?

read the operators guide, most cars and book
state , this the alarm system is failing. (malfunctioning)
there are usually 3 states
light off,
light on
and flashing. (my book says, get it serviced)

Did all this happen at the same time..You have a computer thats called the GEM module..It controls all your interior stuff..It grounds different circuits to make them operatable..Sounds like to me that you have a ground wire broken..Look around under the dash and see if there is any wires that may be loose or broken..The grounds should be either behind the kick panel or maybe on the back in the rear of the dash..If you have a manual you can follow a wire print to locate them..

you gotta check the door switches, one of them is faulty,

check all fuses under dash it mightt be a switch though

red light? this is a factory alarm?? Is GM on the key fob? factory alarms dont have "motion sensors" and very few aftermarket alarms do. roll down the window and set the alarm, now open the door and see if it lights off.

Had a couple of the same issues with 1997 f-350. It turned out to be the 4-way flasher button on top of the steering colum

There is a electric contact in the door to turn on the dome light when open and off when closed. It sounds like that switch is bad or the wire attached to it has fallen off behind the doorsill. It may be another door though, since all work the dome light. Try opening the other doors one by one to see if they light up the dome. Theres no guarantee because the seat or seatbelt may come into effect.

fuse was out for the lighter--heat may be a thermostat-will find out--no solution for the light situation, yet.

its under dash in a little square shape buzzer has been knocked loose or burnt out

Check all your fuses.