The coolant sensor code will erase automatically after 50 engine starts. That one normally does not turn the Check Engine light on after subsequent engine starts. You might have to cycle the ignition switch off and back on to turn the light off.
The humming / vibrating fan motor is a dandy observation. Some people actually complained they could hear the fan running when stopped in traffic. To address that concern, the engineers started using this "electronic fan relay" that you replaced already. It varies the duty cycle of the voltage that runs the fan motor to run it at the slowest speed possible that will still get the job done. "Duty cycle" means the voltage to the motor turns fully on and fully off many times per second. The percentage of on-time is varied to adjust the average voltage and speed. It's that rapid switching that makes the humming sensation.
Saturday, February 19th, 2011 AT 9:06 PM