GM Service Manual Online
For 1990-2009 cars only

Faulty electrical connections and faulty wiring cause most intermittent faults. Damage to the Electronic Variable Orifice/Passlockā„¢ module itself is rarely the cause of such a problem. For a detailed explanation on how to locate and repair an intermittent conditions, refer to Intermittents and Poor Connections Diagnosis in Wiring Systems.