THE STARTER INSULATED CIRCUIT TEST:

 Loose or dirty connections or defective cables represent a power loss between the battery and the starter. Circuit resistance tests are made to determine if the insulated cable, switches, and ground connections can carry the current demanded by the starter. This resistance is indicated by a voltage drop. VOLTAGE DROP is the voltage expended in overcoming resistance in a given circuit. Permissible voltage drop in the average starter insulated circuit is 0.3 volt. The voltage drop allowed in this circuit is 0.1 of a volt per cable or switch. If the resistance is excessive, the result will be an extreme power loss in the starting system. When a starter motor is in operation, the high-amperage draw magnifies this seemingly low resistance value. This greatly reduces the efficiency of the entire starting system. Therefore, the circuit resistance tests are performed while the system is under normal cranking load.

To test the insulated circuit, one voltmeter lead is connected to the insulated battery terminal and the other voltmeter lead is connected to the large armature terminal on the starting motor or solenoid. Crank the engine and observe the voltmeter. If the voltage drop for the entire circuit is not excessive, objectionable resistance does not exist and no further testing is necessary. If the test results indicate excessive resistance, separate detailed tests of each component in the circuit must be conducted.

Starter insulated circuit tests