This Preliminary Information communication provides information to the technician on the steps to diagnose and repair vehicles were the engine cooling fan intermittently stops working. This concern may be caused by water intrusion into the forward lamp harness. If the wiring harness is stretched, or side loaded, where the cooling fan module connector plugs in, this may allow water to wick down the harness, past the weather pack seals, and into the connector itself. Technician will first need to inspect the forward lamp wiring harness to cooling fan module connector for the presence of moisture and/or corrosion. If either is found, the fan control module and the forward lamp harness will both need to be replaced. If no water or corrosion is found after inspecting this connection, refer to Service Information continue with regular diagnosis. If components are replaced the technician will gain access to G101 and G102. With access to both to both G101 and G102 remove any corrosion that is found on either ground. When the grounds are clean and free of corrosion, apply about a half inch length of butyl tape around the wire connection to the ground screw. Once this has been done, cut two patches of butyl, about 2.5 inch square, and apply over the ground screw on both chassis grounds.
