Product review (5 stars): Supco RCO410 Kit Fixed My Kenmore Side-By-Side
This Supco RCO410 start capacitor kit solved my "refrigerator not getting cold" problem and at a fraction of the cost of the original replacement unit,(under $15 from Amazon), not to mention the cost if I would have had a repairman come out to my house.  Start by removing the refrigerator electrical cord from the wall and remove the bottom cover where the compressor is located.  Assuming that the cutout relay/capacitor assembly to your compressor is bad (mine had a bad smell), remove and discard the old unit assembly after cutting the power wires to the unit.  Mine were the red and white wires but yours may be different.  In any case, these two cut wires bring the 120 VAC to the red and black wires of the start capacitor unit.  Strip the insulation back on the two cut wires and hook them up to the pre-stripped red and black wires of the start kit capacitor using the provided wire nuts.  It does not matter which of the pre-stripped red & black wires from the capacitor unit are connected to the power wires cut from the old relay, because AC does not care about polarity.  This leaves 3 wires of the start kit capacitor remaining to be hooked up to the compressor.  Make sure that you identify the compressor pins correctly.  There are 3 pins coming out of the compressor.  Two of the pins should have a resistance of around 10 ohms between each other, therefore the remaining pin is the "common".  The remaining 3 wires of the capacitor unit has spade lugs that will easily attach to the compressor pins.  The black wire spade lug of the capacitor goes to the common pin on the compressor.  The measured resistance between the common and the other 2 pins on the compressor should be approximately 6 ohms and 4 ohms respectively.  The white wire spade lug from the capacitor goes to the pin measuring 6 ohms (start winding) and the red wire spade lug goes to the pin measuring 4 ohms (run winding).  Test repair by plugging in the refrigerator to see if the compressor is running. Allow about 15 minutes or so to make sure that the refrigerator is becoming cold, then unplug refrigerator wall plug, secure capacitor assembly such as with a nylon tie strap, install refrigerator back cover, plug in the refrigerator to the wall and slide into place.  There are plenty of do-it-yourself videos on YouTube, but be careful on how the 3 pins on the compressor are wired.  I say this because mine were upside down from what most videos show.  My refrigerator has been running fine to present date (about 2 weeks) with no further problems.  At this point, I would highly recommend the RCO410 capacitor kit.  If it doesn't work for you, all you are out is a little of your time and less than $15 bucks.  Good luck!