Symptom: *ALL DOORS FAIL TO LOCK FROM ANY SWITCH
WARNING: This page is about a different car, the 2003 Dodge Dakota. However, it is still accessible from the selected car via links, so may be relevant.
POSSIBLE CAUSES
DOOR LOCK RELAY OUTPUT CIRCUIT SHORT TO GROUND
KEY-IN IGNITION SWITCH SHORTED
KEY-IN IGNITION SWITCH SENSE CIRCUIT SHORT TO GROUND
CENTRAL TIMER MODULE - DOOR LOCK OPEN
CENTRAL TIMER MODULE - KEY-IN IGNITION SWITCH SHORTED