Older tech laughed at my meter and now I check amp draw first on every fridge call
Six months back I was on a fridge call in Sacramento and had already swapped the defrost timer and the thermostat, still not cooling right. A guy who has been doing this 30 years was working the next building over and stopped by, watched me for a minute, then said "you're parts swapping, put your meter on it." He meant the compressor. I had been skipping amp draw because it felt like extra steps on a call that was supposed to be easy. Turns out the compressor was pulling way less than its rated amps, which pointed straight at a bad start relay and run cap combo, not the stuff I replaced. Since then the first thing I do on any fridge no cool is clamp the meter and write the actual number down before I touch anything. Cut my callback rate from about 4 a month to maybe 1. If you had a tech call you out on your diag order, what was the thing that flipped for you?
The start relay and run cap thing is close but not the whole story there. Low amps on a compressor usually points to it not pulling its load, which sounds like a weak winding or a dead run cap more than the relay itself. The relay is what sends power to the start winding, and if it fails the compressor just hums and trips overload, it doesn't quietly run light. I ran into this on a Sub-Zero last year, amps were sitting at 2.1 when the tag said 8.4, turned out the run cap had drifted way off and the compressor was barely turning over. Replaced the cap and amps came right back up. The relay was fine the whole time.