Ford: 98 ford windstar backhatch, door latch assembly, ford windstar

Question
I have a ford windstar 98 3.0 engine. my question is what will cause the inside lighst stay on after i shut the backhatch?? the idiot lights says the door is ajar but it isn't, this only does this when it rains.. what can i do to get the sensor to realize the hatch is closed and get my inside dome lights to turn off??

Answer
Most commonly, the passenger Sliding door is the culprit.
B1322, B1330, B1334, B1335.  



Problem:  The door ajar switch is sticking.  



Test & Fix:  The generic electronic module (GEM) sends out a voltage through a dropping resistor to each of the 4 door switches to monitor whether the doors are open or closed. The front doors and rear tailgate switches close (ground) when the doors are opened. This pulls the voltage low which signals the GEM that a door is open and activates the interior lights and door ajar indicator. The sliding side door operates opposite of the other 3 doors. This switch opens when the door is opened allowing the GEM to see voltage on this wire, indicating an open door. To start diagnosis, gain access to connector C-250, a black 14 cavity connector located behind the right front kick panel. The left front door wire is Black/Yellow, the right front door wire is Black/Pink and the sliding side door wire is Black/White and run through this connector. Disconnect connector and check continuity to ground on these wires with all doors closed. If there is continuity on either the Black/Yellow or the Black/Pink wire with the doors closed, the switch in the corresponding door is faulty and needs replacing or the wire is grounded from the connector to the switch. The switch is located in the door latch assembly. To verify the switch is defective, unhook the connector at the latch switch. If the circuit is now open, the switch is at fault. If the circuit is open on the Black/White sliding door circuit, the problem is either a poor connection in the sliding door contacts or a defective latch switch. Diagnosing the rear liftgate circuit requires removing the interior door trim to gain access to the 6 pin connector, C-901, at the left hand top of the door. This circuit operates the same as the front doors except there is a switch on each latch, hooked up to the same wire. Check continuity on the Black/Light Blue wire at the connector with the door closed. If this circuit is grounded, unhook 1 switch at a time to see which one is sticking closed and replace as neccessary.