Clean terminals, re-clamp firmly, or check battery with a voltmeter to see if it is below 7V. Battery was recently charged or driven
Regularly check the test leads and inductive pickup for cracks or damage to prevent electrical shock. equus 3022 tester manual full
Check that the clamps are making secure, metal-to-metal contact with the terminals. If the contact is clean and tight but the screen remains blank, the battery voltage may be below the minimum threshold required to power the device (typically under 7 Volts). Clean terminals, re-clamp firmly, or check battery with