HUB 1788175 - Caterpillar

Head, Tail, And Dash Lights
The head, tail, and dash lights get their power from a 15 amp automatic reset circuit breaker on the back of the fuse panel under the instrument panel. The 7N8010 Switch for the lights has three positions.1. (DOWN) OFF.2. (MIDDLE) Head and tail lights ON.3. (UP) Head lights, tail lights, and dash lights ON.The shorter DK BL wire connects to terminal 2, the longer DK BL wire connects to terminal 3, and the T/DK BL wire connects to terminal 6.
Figure 21. Head, Tail, and Dash Lights Circuit
Figure 21a. 7N8010 SwitchStop Lights
The stop lights get their power from the 10 amp fuse marked "STOP LIGHTS & BACKUP ALARM" on the fuse panel under the instrument panel.
Figure 22. Stop Lights CircuitRear Flood Lights
The rear flood lights get their power from the 15 amp fuse marked "REAR FLOODS" on the fuse panel under the instrument panel.
Figure 23. Rear Flood Lights CircuitAuxiliary Front Flood Lights
The auxiliary front flood lights get their power from the 10 amp fuse marked "AUX" on the fuse panel under the instrument panel. The schematic shows the wiring for a machine with or without a cab.
Figure 24. Auxiliary Front Flood Lights CircuitService Meter
The machines have a 6N5906 Electronic Service Meter. The meter gets its power from the 10 amp fuse marked "HR METER & START AID" on the fuse panel under the instrument panel. There is a normally open 2N7744 Engine Oil Pressure Switch that makes a ground for the meter. When the engine is running and the oil pressure is greater than 6 psi, the switch closes and activates the service meter.This service meter uses a solid-state (no moving parts) timing circuit that sends a timing pulse (current for a short time) every 36 seconds to the solenoid that moves the counter. When the engine is started and the meter first gets power, it takes a minute or more for the first movement of the counter. The meter works on a 24 volt negative ground system only.The 6N5906 Meter has a very good service record. If the meter does not work, make sure that the red wire has 24 volts and that the black wire is at ground. Most meter failures are really failures of the oil pressure switch that makes the ground for the circuit, or of the wiring to the meter.
Figure 25. Service Meter CircuitBack-Up Alarm
The back-up alarm warning system has a 6P8576 Alarm installed behind the radiator. The alarm has a solid state (electrical, no moving parts) circuit that makes the sound go on and off when it has current. The back-up alarm gets power from the 10 amp fuse marked "STOP LIGHTS & BACK-UP ALARM" on the fuse panel under the instrument panel. The back-up alarm is controlled by a 9N1750 Microswitch that is part of the transmission neutralizer group. The switch is inside an aluminum housing where the forward-reverse transmission cable is fastened to the transmission. The switch stays open in NEUTRAL and FORWARD, but closes when the