Battery Cable Test With Dual-Battery Locations; Starter Solenoid Circuit Test - Borg Warner Delco Remy 28MT Diagnostic Procedures Manual

3-10. BATTERY CABLE TEST WITH
DUAL-BATTERY LOCATIONS
(SEE FIGURE 3-4)
This test applies if the vehicle has more than one battery location
and the batteries are connected to the starter by separate cables.
Essentially, this is the same as the previous test with a single
battery location (paragraphs 3-7 through 3-9) except as follows:
3-11. TEST PROCEDURE (See Figure 3-4).
If the system usually operates on 24-volts, connect one battery
at each location to the starting motor, making a temporary 12-
volt system.
1. Disconnect batteries from first set.
2. Test second set cables as described in paragraph 3-8 except
apply 250 amp load at starter (125 amp for 24-volt system).
3. Use same voltage drop or loss limits as specified in paragraph
3-8.
4. Reconnect first set of batteries and disconnect second set.
5. Repeat steps 2 and 3 for first set of cables.
6. Replace cables or repair circuits with excessive voltage drop.
3-12. TEST COMPLETION. If temporary 12-volt test connections
were made for 24-volt system, reconnect batteries to vehicle
specifications for 24-volt operation before starting vehicle.
However, if the tests following are to be performed, keep the
temporary 12-volt hook-up.
NOTE
FIRST SET
SECOND SET
NEGATIVE
VOLTAGE
LOSS
FIGURE 3-4. Battery Cable Test -
Typical Dual Box 12-Volt System
3-13. STARTER SOLENOID CIRCUIT
TEST
The starter shifting in and out, or not pulling in, is often caused by
high resistance in the starter solenoid circuit. When the solenoid
circuit has excessive voltage loss, the starter pinion may not
engage the flywheel. If it does engage, it may drop out too soon
when battery voltage lowers. The solenoid circuit usually consists
of a magnetic switch with leads to and from the starter solenoid.
Some vehicles use only a push-button switch to control the starter
solenoid and this same test applies.
POSITIVE
VOLTAGE
LOSS
CARBON PILE
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