Unplug the cable from its place at the terminal of the negative battery. Remove the switches for testing. With an ohmmeter, test each switch by checking for connection between the right spots on the terminals when the switch is set in each position. When the switch doesn't deliver the expected electrical flow, you must replace it. Release the electrical cord from its connection to the battery's negative terminal. Take out the knee bolster and steering cone covers. Unscrew the attaching screws of the switch to its housing, then lift out the switch. Installation is the reverse of removal.