DIAGNOSIS
A voltage drop test will determine if there is excessive resistance in the battery cable terminal connections or the battery cables. If excessive resistance is found in the battery cable connections, the connection point should be disassembled, cleaned of all corrosion or foreign material, then reassembled.
Following reassembly, check the voltage drop for the battery cable connection and the battery cable again to confirm repair.
When performing the voltage drop test, it is important to remember that the voltage drop is giving an indication of the resistance between the two points at which the voltmeter probes are attached. EXAMPLE: When testing the resistance of the battery positive cable, touch the voltmeter leads to the battery positive cable terminal clamp and to the battery positive cable eyelet terminal at the starter solenoid B(+) terminal stud. If you probe the battery positive terminal post and the battery positive cable eyelet terminal at the starter solenoid B(+) terminal stud, you are reading the combined voltage drop in the battery positive cable terminal clamp-to-terminal post connection and the battery positive cable.
TESTING
VOLTAGE DROP TEST
WARNING:
PERSONAL INJURY AND/OR VEHICLE DAMAGE MAY RESULT.
The following operation will require a voltmeter accurate to 1/10 (0.10) volt. Before performing this test, be certain that the following procedures are accomplished:
Refer to Battery Charging in the index of this service manual for the location of the proper battery charging procedures. Refer to Battery in the index of this service manual for the location of the battery diagnosis and testing procedures, including the proper battery load test procedures.
(1) Connect the positive lead of the voltmeter to the battery negative terminal post. Connect the negative lead of the voltmeter to the battery negative cable terminal clamp (Fig. 13). Rotate and hold the ignition switch in the Start position. Observe the voltmeter. If voltage is detected, correct the poor connection between the battery negative cable terminal clamp and the battery negative terminal post.
Fig. 13 Test Battery Negative Connection Resistance - Typical
1 - VOLTMETER
2 - BATTERY
(2) Connect the positive lead of the voltmeter to the battery positive terminal post. Connect the negative lead of the voltmeter to the battery positive cable terminal clamp (Fig. 14). Rotate and hold the ignition switch in the Start position. Observe the voltmeter. If voltage is detected, correct the poor connection between the battery positive cable terminal clamp and the battery positive terminal post.
Fig. 14 Test Battery Positive Connection Resistance - Typical
1 - VOLTMETER
2 - BATTERY
(3) Connect the voltmeter to measure between the battery positive cable terminal clamp and the starter solenoid B(+) terminal stud (Fig. 15). Rotate and hold the ignition switch in the Start position. Observe the voltmeter. If the reading is above 0.2 volt, clean and tighten the battery positive cable eyelet terminal connection at the starter solenoid B(+) terminal stud.
Repeat the test. If the reading is still above 0.2 volt, replace the faulty battery positive cable.
Fig. 15 Test Battery Positive Cable Resistance - Typical
1 - BATTERY
2 - VOLTMETER
3 - STARTER MOTOR
(4) Connect the voltmeter to measure between the battery negative cable terminal clamp and a good clean ground on the engine block (Fig. 16). Rotate and hold the ignition switch in the Start position.
Observe the voltmeter. If the reading is above 0.2 volt, clean and tighten the battery negative cable eyelet terminal connection to the engine block.
Repeat the test. If the reading is still above 0.2 volt, replace the faulty battery negative cable.