Aftermarket (Add-On) Electrical And Vacuum Equipment

WARNING: This page is about a different car, the 2004 GMC Sierra, 2004 GMC Cab & Chassis Sierra, 2004 Chevrolet Silverado, and 2004 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

Any equipment installed on a vehicle after leaving the factory that connects to the electrical or vacuum systems of the vehicle defines aftermarket (Add-On) electrical and vacuum equipment. The vehicle design makes no allowances for this type of equipment.

NOTE: Do not attach add-on vacuum operated equipment to this vehicle. The use of add-on vacuum equipment may result in damage to vehicle components or systems.

NOTE: Connect any add-on electrically operated equipment to the vehicle's electrical system at the battery (power and ground) in order to prevent damage to the vehicle.

The add-on electrical equipment, even when installed to these strict guidelines, may still cause the powertrain system to malfunction. This may also include any equipment which is not connected to the electrical system of the vehicle such as portable telephones and radios. Therefore, the first step in diagnosing any powertrain problem is to eliminate all of the aftermarket electrical equipment from the vehicle. After this is done, if the problem still exists, diagnose the problem in the normal manner.