A method comprising: receiving, by at least one processor connected to a display, a download including (i) an image representative of a vehicle component, wherein the image depicts a wiring harness connectable to or part of the vehicle component, (ii) symbol data associated with a first symbol for a first circuit within the wiring harness, (iii) a set of selectable identifiers, the set including one or more selectable identifiers, and (iv) supplemental information associated with the vehicle component, wherein each selectable identifier of the set indicates a respective portion of the supplemental information associated with the vehicle component and, when selected, causes the display to display the respective portion of the supplemental information; displaying, on the display after receiving the download, at least a portion of the image and the first symbol without displaying the set of selectable identifiers,; receiving, by the at least one processor while the image and the first symbol are displayed on the display without the set of selectable identifiers, a first input corresponding to selection of the first symbol; displaying, on the display in response to receiving the first input, the set of selectable identifiers; transmitting, by a vehicle interface device, a request for live data values associated with a parameter identifier, "PID", used by the vehicle component; receiving, by the vehicle interface device, the data values associated with the PID; converting, by the at least one processor, the received data values to obtain electrical measurements; displaying, together with the set of selectable identifiers, multiple electrical measurements obtained from the vehicle for the first circuit over a period of time as a graph or graphs; receiving, by the at least one processor while the set of selectable identifiers is displayed, a second input corresponding to selection of a first selectable identifier from the displayed set of selectable identifiers; and displaying, on the display in response to receiving the second input, the respective portion of the supplemental information indicated by the first selectable identifier. receiving, by at least one processor connected to a display, a download including (i) an image representative of a vehicle component, wherein the image depicts a wiring harness connectable to or part of the vehicle component, (ii) symbol data associated with a first symbol for a first circuit within the wiring harness, (iii) a set of selectable identifiers, the set including one or more selectable identifiers, and (iv) supplemental information associated with the vehicle component, wherein each selectable identifier of the set indicates a respective portion of the supplemental information associated with the vehicle component and, when selected, causes the display to display the respective portion of the supplemental information; displaying, on the display after receiving the download, at least a portion of the image and the first symbol without displaying the set of selectable identifiers,; receiving, by the at least one processor while the image and the first symbol are displayed on the display without the set of selectable identifiers, a first input corresponding to selection of the first symbol; displaying, on the display in response to receiving the first input, the set of selectable identifiers; transmitting, by a vehicle interface device, a request for live data values associated with a parameter identifier, "PID", used by the vehicle component; receiving, by the vehicle interface device, the data values associated with the PID; converting, by the at least one processor, the received data values to obtain electrical measurements; displaying, together with the set of selectable identifiers, multiple electrical measurements obtained from the vehicle for the first circuit over a period of time as a graph or graphs; receiving, by the at least one processor while the set of selectable identifiers is displayed, a second input corresponding to selection of a first selectable identifier from the displayed set of selectable identifiers; and displaying, on the display in response to receiving the second input, the respective portion of the supplemental information indicated by the first selectable identifier.