Cadillac 16513910 Headlamp Capsule Assembly

If one headlight works only high or low beam check battery voltage at the headlight electrical connector if voltage is present replace the headlight assembly or bulb if either is available, but if not use the headlight wiring diagram to troubleshoot. For headlights that do not work on either beam, inspect battery voltage and ground at the electrical connector; if voltage is present, test the ground terminal of the headlight; if both are present, replace headlight assembly or bulb if available as a separate unit. If either of the voltage or the ground is missing, consult the wiring diagram of the house. Further, check the operation of headlight switch and replace it if it is either bad or has been faulty at times. If they are very dim, then check battery voltage and ground at electrical connector; if there is voltage, look for the ground circuit for headlamp connector and clean and repair as needed; if voltage is much lower at connector than battery, then find the location of the voltage drop on the basis of the wiring diagram.