Checking Turn Signal Wiring

Video Transcript

"In this clip we're going to talk about the proper method to remove, replace, and diagnose a turn signal bulb and socket on a 91 Ford Explorer. In this step we're going to talk about the proper service procedure for testing the integrity of our wiring using a test light. We're going to check the positive and negative side of the wires inside here through the headlight, which is going to turn on the parking light portion of this socket through the turn signal and through the hazard flasher portion of the socket. I have an assistant in the vehicle who's going to go ahead and turn on the left turn signal. I'm checking the ground side. What I do is have my test light hooked up to the positive part of the battery and I'm going to check the wires and see if my ground circuit has its integrity. This is the ground circuit here and as you can see it lights up. That means that all of the wiring from here all the way through the switch and back to the battery is good. I'm going to go ahead and switch my test light from the positive to the negative side and we're going to check the positive side of the circuitry, where the power is sent. As you can see my light lights up. What that does is indicates that the same thing as the ground did, from here all the way through the switch and back to the battery including the relays of the flasher all the integrity is there. You can also use a known good bulb. If you got a brand new bulb from the parts store and you don't have a test light you can plug in a know good bulb as you can see it's flashing properly. I'm going to have my assistant step in and go through the various functions. This bulb does have two elements in it. Go ahead and hit the hazard. There's the hazard portion of it. The turn signal and the hazard use the same element, but a different switch. Go ahead shut off the hazard and turn on the head lights. That is the marker light portion of it, as you can see there's two elements inside there. The other one is lit up. That is the proper way to check all the wiring, relays, switches, and flashers in your turn signal system."