Intermittent Problem Diagnosis
WARNING: This page is about a different car, the 1995 Mercury Villager. However, it is still accessible from the selected car via links, so may be relevant.
Intermittent fault testing requires duplicating circuit or component failure to identify the problem. These procedures may lead to the computer setting a fault code which may help in diagnosis.
If problem vehicle does not produce fault codes, monitor voltage or resistance values using a DVOM while attempting to reproduce conditions causing intermittent fault. A status change on DVOM may indicate a fault has been located.
Use a DVOM to pinpoint faults. When monitoring voltage, ensure circuit has power applied to it. Significant changes on DVOM during test procedures indicate area of fault.