This problem affects 1996-2002 G-series vans (Chevy Express and GMC savana). The powertrain control module/vehicle control module (PCM/vcm) corrodes over time and the case enclosing the computer splits open allowing water to enter the vehicle's electrical system. GM has acknowledged this problem in technical service bulletin 02-06-04-020, attributing it to location of the PCM/vcm and design of the engine wiring harness deflector. This deflector acts much like a "rain gutter" to route water away from the computer. It was poorly designed and instead dumps water directly on to the computer triggering corrosion. The corrosion may also be the result of galvanic action (two dissimilar metals generating an electrical charge) as the computer case is alumionum and screws holding it together are steel. A small claims court action filed against GM and the dealership immediately resulted in an offer from GM to pay for all repairs (prior to any hearings). This leads us to believe they are very aware of this problem and may in effect have a "'secret warranty" in place. Total repair cost was $1,400 but it could have been much more since we chose to "dry out" the electrical system rather than replace the entire wiring harness (more than $2,000 parts and labor).

- Fredonia, WI, USA