I'm at my wits end! 2009 Silverado 6cyl. 90,000 mi. Keeps giving the engine hot/ac turned off warning even though the engine is not hot. The only way I can clear this message is to disconnect the battery for a while. Sometimes this will fix the problem for a day or two...sometimes just for a few minutes. I have changed both the thermostat and the engine coolant temperature sensor, but the problem persists. My guess is that it is a computer malfunction. Is there some way I can disable this?