A method of operating a control device includes performing an open load test or a current leakage test. The open load test includes activating a first current and then a second current and sensing with the first current and the second current activated, respectively, a first voltage drop and a second voltage drop between charge distribution pins and charge sensing pins of the control device. Respective differences are calculated between the first voltage drop and the second voltage drop sensed with the first current and the second current activated, respectively. These differences are compared with respective thresholds and an open circuit condition is declared as a result of the differences calculated reaching these thresholds.