Freezer compressor not running

Sears Coldspot Freezer 106.724240
The overload/relay is firing off every couple of minutes but is not starting the compressor. The compressor is very warm, but not hot to the touch. When the relay first kicks in, there is voltage coming off the overload connector to the compressor (lower right pin). After a couple of seconds, the relay sparks and the voltage is removed. Either the overload or the compressor is humming during the time the voltage is applied, i.e. I’m hearing more than just the click from the relay when it shuts off. The overload is a wire wound unit, so I have my doubts that it could be bad, but I could be wrong. The original overload #548836 has been replaced by the manufacturer with an overload/relay using the same part number and requires some rewiring. Before going to that effort, is there any way to determine if it’s really the overload or the compressor? As a side note, the defroster timer went bad and got stuck on the compressor cycle. This would have caused me other problems with the defrost, but I’m not sure it would have caused the compressor problem.