After driving my 1988 Voyager a few blocks today at approx. 40 degrees ambient temperature, I popped the hood and left the engine running. The upper radiator hose was still cold, meaning the engine had not reached anywhere near operating temperature. The radiator fan then clicked on and ran for probably a minute. Neither the A/C nor the defroster was on.
I know that the SMEC turns on the fan through the fan relay based on information received from the coolant temperature sensor. The sensor has been replaced probably within the last year.
Any ideas? I doubt that this could impair driveability, but it just seems odd that the fan is turning on so soon and while the engine is still relatively cool.
Thanks everyone for your input.