I am having trouble with the tach/hour meter on my 2240 (same cluster as many same age JD's): tach stopped working and hour meter began racing 10 minutes to turn over an hour. all other lights/guages worked. I obtained a used supposedly working meter cluster. again all gauges worked, this time the hour meter was fine, but the tach showed nothing. Before I return it, I wondered if anyone could tell me where the sensor (or sending unit) for the tachometer would be located. This is an all electronic cluster, not one with a cable. If you have any suggestions about trouble shooting this item, let me know before I throw money to get a new one. Thank you