Diagnostic Aids
WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 1997 GMC Savana Special, 1997 GMC Savana Camper Special, 1997 GMC Savana, 1997 Chevrolet RV Cutaway, and 1997 Chevrolet Cutaway. However, it is still accessible from the selected car via links, so may be relevant.
An intermittent may be caused by a poor connection, rubbed-through wire insulation or a broken wire inside insulation. Inspect VCM harness connectors for backed-out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal-to-wire connection, and damaged harness.
If connections and harness are okay, using DVOM connected between affected terminals and ground, monitor voltage while wiggling related connectors and wiring harness. If a failure is induced, voltage will change. A change in voltage will assist in isolating location of fault.