GMC 19152823 Backup Switch

As of 1995 models, this switch makes sure your engine can only start when you have it either in Park or Neutral. Additionally, it completes the circuit connecting your backup lights when you switch to Reverse. When you start the engine and it's not in Park or Neutral, the switch that controls this needs either readjusting or replacing. Glue the safety stand under the car and disconnect the power wire from the control switch. When the key is off, look for current flowing between the switch terminals: there should be connection when the shift lever is in Park or Neutral and no connection in other positions, except for connection to the back-up lights while Reverse is chosen. When the switch shows problems, adjust it first and try again. If the switch keeps failing tests, you must replace it. Before taking off the shift control switch, apply the parking brake and put the transmission into neutral. Cut power from the vehicle, lift it onto jack stands, disconnect the battery's negative end, remove the shaft nut, unplug the electrical connection, unscrew the mounting bolts, and pull the switch off the shaft using care. To put the switch in, follow the manufacturer's guide to adjust it with their special tool. Make sure the detents match the tool's points and the locator pin is right where it should be. Before putting the switch on the shaft, clean away any rough edges and smooth them with a file. Then center the switch's flat sides over the shaft's flat sides, place it on, and slide until the mounting bracket's bottom touches the transmission ears. After putting the switch mounting bolts on and tightening them to their needed force, take out the tool for adjustments, and you're done with the installation. Turn everything back around to cut it all loose like you did at the beginning, except fasten the handle's holding nut to the correct tightness.