I don't have access to the UUT schematic or components. The UUT is a 12VDC Timer that powers a 12V relay. My plan was to use this tester to test how long the relay is closed for by connecting the relay to ground and the other terminal of the UUT to pin 2 on the arudino circuit.
For the UUT - when it recieves power, the output (relay) is closed for the ten seconds and won't reset until power is taken away.