Not sure since my 4610 does not use this part, but maybe someone who has replaced one on a 4500 or other 4X00 tractor will respond.
You can pull the relay and test it with a multi-meter first before replacing if you like. Power initially flows through relay pin 30 to pin 87A and then to the PTC (thermistor). After the PTC warms and opens, the K3 relay energizes and switches the relay wiper to pin 87 to open the pull-in coil circuit (and reset the PTC). If the un-energized K3 relay has low resistance between terminals 30 and 87A, it should be fine to activate the pull-in coil (if the PTC (thermistor) is good).
You can also energize the relay by applying 12 Vdc across relay terminals 85 and 86 (polarity not important), and make sure that there is no longer continuity between relay terminals 30 and 87A.
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