In theory, the vehicle is overheating. Does it seem to be overheating? If the cooling system has been drained, sometimes these motors can have some air trapped in the cooling system. When the red light is on, can you touch the upper radiator hose, is it hot? If it is not hot, there is no flow. This could be for a few reasons. The thermostat is not open(if there is air behind it, it may not open). There could be a restriction in the system, if you replaced the radiator I would not suspect that. The water pump could be faulty, have never seen it but it is a possibility. You could also have a blown head gasket. Is the coolant level full? Here is what code description for F49 states.
To protect the vehicle's cooling system from overheating, the BCM commands the compressor clutch to disengage if the coolant exceeds 126 C (259 F). Also, if the A/C high pressure refrigerant temperature exceeds 93 C (200 F), the clutch is turned "OFF" to prevent refrigerant "blow-out." Code F49 is stored by the BCM whenever the clutch is being disengaged due to one of the above conditions. Customer complaints of "insufficiant cooling" or "engine overheating" may be associated with this code. If a hard or intermittent code F49 has been stored, the coolant and refrigerant systems must be investigated for the cause of a high temperature condition. Possible causes would include blockage in coolant flow, blockage in refrigerant flow or insufficiant air flow over radiator/condenser.
Sorry, at first I was mislead, and what misled me was the word fan. If I remember right, this also has a cooling fan warning light, and there is different diagnostics associated with that. It sounds like you have an overheat condition for some reason.
Friday, July 9th, 2010 AT 11:32 PM