Electrical Troubleshooting - Cub Cadet RZT-S Professional Shop Manual

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Electrical Troubleshooting

1. The first step in troubleshooting is to always verify the complaint. Defining and verifying the problem reduces
the possibility of misunderstanding and helps clarify the diagnostic approach.
2. The next step is to check the simple stuff first:
• Check the fuse or fuses:
NOTE: Failure of any fuse is an indication that there is a problem of some sort in the circuit that the fuse pro-
tects.
• Look for obvious physical damage.
• Use the hour meter and indicator lamps as a guide to direct the search. As an example, when diagnosing
a "no-crank" condition on a RZT-S mower: if the PTO light is lit on the hour meter but the technician has
visually verified that the PTO clutch is not engaged, the PTO circuit would be a reasonable place to check
for problems.
• Check the battery.
IMPORTANT: A valid diagnosis of many systems cannot be made without full system voltage applied.
3. Take a methodical approach to finding the problem. As a rule of thumb, start at one end of the circuit and work
to the other.
4. The next step is to decide what method to use to troubleshoot the circuit.
• If checking a safety circuit that grounds the magneto, use an Ohms meter to test for continuity.
• If checking a safety circuit that enables a starter motor or accessory, use a volt meter to confirm the pres-
ence of power at each junction in the system.
• If a circuit does not work at all, look for a short or an open.
• If the circuit works slowly or intermittently, look for resistance by doing a voltage drop test.
NOTE: In all diagnostics, it is very important to understand the circuit that is being checked. The use of a sche-
matic is recommended, even if a technician is thoroughly familiar with the system.
5. Testing for opens/shorts
NOTE: When checking circuits for continuity, disconnect the circuit at the nearest plug and use the metal ter-
minals of the plug as a connection point for the test probes. DO NOT STAB THE WIRES.
NOTE: When checking circuits for voltage, back-probe the terminals nearest the point to be checked. DO NOT
STAB THE WIRES.
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