CARRIER-YM 3148659 - Caterpillar

the multimeter in the DCV range to find starting system components which do not function.Move the start control switch in order to activate the starting solenoids. The starting solenoid's operation can be heard as the pinion of the starting motor is engaged with the ring gear on the engine flywheel.If a solenoid for a starting motor will not operate, it is possible that the current from the battery did not reach the solenoid. Fasten one lead of the multimeter to the connection (terminal) for the battery cable on the solenoid. Connect the other lead to a good ground. A zero reading indicates that there is a broken circuit from the battery. More testing is necessary when there is a voltage reading on the multimeter.The solenoid operation also closes the electric circuit to the motor. Connect one lead of the multimeter to the solenoid connection (terminal) that is fastened to the motor. Connect the other lead to a good ground. Activate the starting solenoid and look at the multimeter. A voltage reading of the battery shows that the problem is in the motor. The motor must be removed for further testing. A zero reading on the multimeter shows that the solenoid contacts do not close. This indicates the need for repair to the solenoid, or to the clearance for the starter motor pinion.Perform a test. Fasten one multimeter lead to the connection (terminal) for the small wire at the solenoid and fasten the other lead to the ground. Look at the multimeter and activate the starting solenoid. A voltage reading shows that the problem is in the solenoid. A zero reading indicates that the problem is in the start switch or the wires for the start switch.Fasten one multimeter lead to the start switch at the connection (terminal) for the wire from the battery. Fasten the other lead to a good ground. A zero reading indicates a broken circuit from the battery. Check of the circuit breaker and wiring. If there is a voltage reading, the problem is in the start switch or in the wires for the start switch.Starting motors that operate too slowly can have an overload due to excessive friction in the engine that is being started. Slow operation of the starting motors can also be caused by a short circuit, loose connections, and/or dirt in the motor.