The wiper function could be the Multifunction switch (Wiper/headlamp) or the Central Timer Module (CTM). The CTM also controls the Power Door Lock Functions, however, the is a Technical Service Bulletin TSB 08-23-03 to address this issue. here is a short summary. . The door locks will intermittently lock and/or unlock without any activation of the power door lock switch or a clicking sound may be heard coming from the power door locks (repeated locking or repeated unlocking). The condition may occur more frequently in damp conditions such as driving the vehicle in the rain or taking the vehicle through a car wash. Vehicles that demonstrate this condition may have water weeping into the door/liftgate lock cylinder switches causing the switch to intermittently short across the internal circuit. This in turn may signal the Central Timer Module (CTM) to activate the power door locks. Because of the nature of this problem, it is extremely difficult to diagnose this condition. Therefore, customers that indicate their doors intermittently lock and unlock without having the door lock switch activated or customers that indicate they hear a repeated clicking noise coming from the door locks should have the door lock swtches replaced.
As far as your 4 WD switch, it sounds as though the switch has failed. As the position of the selector switch varies, the resistance between the Mode Sensor supply voltage pin and the Mode Sensor output will vary. Hardware, software, and calibrations within the Transfer Case Control Module (TCCM) are provided that interpret the selector switch resistance .
