Item: DROK® Digital DC 12V Ammeter Panel Amp Meter Gauge DC 0-+/-50A Current Tester AC/DC 8-12V Current Monitor with Blue Back-light Black Font for Automotive Vehicle
Purchased through Amazon.com

Problem: The meter powered up fine, until I attached the test leads to the supplied shunt. At first it came on and showed a minus sign with no digits, then after a few seconds all display went blank- only back light remained on. I have three amp meters, two of which were hooked up and suffered the same fate, the third unattached meter simply shows zero current- (not attached to any thing but supply power). Using my digital meter I saw less than.01VDC across the shunt, indicating very little current- so there was not over 50 amps current in circuit. The shunts are hooked in series with the positive post of a 12 V battery, and expected currents are less than 20 amps when in use, but at the time nothing was running so current should have been extremely low.

Summery: I have been in electronics for nearly forty years and my application is fairly simple, so I suspect either product defect or design defect. So now what do I do? Or more to the point here, now what are you going to do to remedy the problem encountered?