Interior lights not coming on when door is opened.

On my 1997 Mercury Sable 3.0L V6, the interior lights not coming on when door is opened.

The door ajar light on the dash was takes a long time to disappear after you close the door and drive the vehicle. However, the dome light does not come when you open the door.

I can turn the dome light by manually flipping the on/off switch next to the dome light. However, the dome light does not turn ON if I manually turn the dimmer switch all the way up.

I fixed the door ajar light by spraying WD-40 as what other folks have suggested. Now the door ajar light on the dash immediately goes away after closing the door.

The problem is still with the dome light not coming ON when opening the door or turning the dimmer switch all the way up. Any advise is appreciated. Thanks.

Check the connections on the switch you sprayed in your door. May be that the wires have corroded and the connection is bad.

I'm looking at the schematic diagram and it seems that most relay including the dome light is controlled by Generic Electronic Module (GEM). I've read that it needs to be programmed when putting a new GEM. Do I still need to reprogram the GEM when using a used GEM from the same model and year of my 1997 Mercury Sable 3.0L V6 SOHC?

Update:

I checked the fuses and none of them are open.

I opened the dome light cover and found three bulbs. You are right. Both sides are for the map lights and the center one is for the Dome Light. The bulb is not burned out and the filament is still intact. Come to find out that the metal part on side of the bulb is not making contact of the wire filament. I pushed in the metal end of the bulb and the light turned ON even though all 4 doors are closed. The dimmer switch is down. So, I guess the problem now is with the door pin switch.

Update:

Re-sprayed the door switches with WD-40 and now the dome light will turn off after the door is closed. I might try to get a contact cleaner when I get to the store.