Tried a cheap multimeter vs a Fluke on a fridge compressor call

I had a fridge that was acting like the compressor was shot, no start relay click, nothing. My old $20 meter was giving me wild readings on the ohms, like 12 and then 8 and then nothing. I thought for sure the compressor was toast and started telling the customer they'd need a new fridge. But I had my buddy's Fluke 117 in the truck from a job last week, so I figured why not double check. Ran the same tests and it gave me a solid 3.2 ohms on the start winding and 2.8 on the run. Turned out the start relay was just crusty, not the compressor at all. That cheap meter saved me nothing because it almost cost me a sale and made me look like an idiot. Anyone else had a cheap tool steer you totally wrong on a simple test?

2 comments

2 Comments

price.jake1mo ago

Just a heads up, a compressor with those good winding readings still should have checked for a short to ground before ruling anything out. Your cheap meter might have been fine on continuity and just struggled with low resistance readings due to dirty leads or a low battery. Your mileage may vary, but I've found that wiggling the probes and cleaning the test points helps even cheap meters give consistent readings.

angela_dixon1mo ago

Yeah, that's a good point @price.jake, but I think people overlook checking the run capacitor under load too. A cap can test fine with a meter but still be weak when the system's running, which throws off the whole diagnosis.