I have a 03 sierra and my check engine light is on and i took it to the auto parts store to have the scanner pluged in and see what was wrong with it . and its not getting power to the connector ... so i checked all my fuses and the are all good even the cig lighter so i checked the wires going to the obdII connector . Im getting power to one wire and im not getting power to the purple one the light bulb bearly lights up ... I dont know what to check or do now...thanks