SWITCH 4329211 - Caterpillar

Gauge Module Lamp Replacement
1. Disconnect the 24V power supply wire to the unit before any disassembly. Consult your service manual or Caterpillar dealer.2. If equipped with a rear mounting bracket, remove the two #6 hex nuts on the rear of the unit and remove the mounting bracket.3. Remove the two #4 hex socket bolts in the bottom of the unit and the two at the top of the unit (one on each side). DO NOT remove the screw located near the bottom on the side of the unit.4. The rear cover can now be removed.
Be careful not to put excessive stress on the ribbon cable connecting the two circuit boards or damage can result.
5. Grasp the gray lamp socket and twist it counterclockwise. Avoid touching the circuit board and components.6. Pull the bulb out of the socket and push the new replacement bulb back in the socket. Make sure the wire controls on the bulb are between the prongs in the socket.7. Push and twist clockwise to "lock" the lamp socket in place in the circuit board.8. Reassemble the rear panel to the enclosure being careful not to pinch the smaller ribbon cable between the castings. Push this cable gently towards the center of the module as the rear cover is put in place.9. Tighten all bolts, replace the mounting bracket and tighten nuts. Reconnect 24V power supply wire.Terminal Strips
Terminal strip terminal screws must be properly torqued to ensure good electrical connections are maintained. Whenever terminal screws are loosened, they should be torqued again to 0.45 to 0.68 N m (4 to 6 in lb).After 1000 service hours of engine operation, and once every 10,000 service hours thereafter, terminal screws should be rechecked for proper torque and adjusted where necessary.Sensors
Sensors are not protected from overvoltage or incorrect hook-up and will be damaged if subjected to either. It is important to check all sensor wires (refer to wiring diagram 4P3116 in Service Manual) for proper voltage, polarity, etc. before connecting a sensor.Vent ports for pressure sensors must be protected from plugging as a result of paint, dirt, debris or other foreign matter.
Sensor supply voltage is regulated to 8 0.5 VDC by the power supply in each module. If a sensor appears to detect and send false readings and/or performing sporadically, the supply voltage should be checked before replacing a sensor. Some sensors will "burn out" if a reverse polarity is applied.Gauge Modules
The sensors, wiring and programmed functions (such as ETR and ETS) should be checked before considering gauge module replacement.The gauge modules can be replaced and are serviced by Caterpillar part numbers.