Ford Explorer, Руководство по техническому обслуживанию и ремонту

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Do not short across or ground any of the terminals on the AC generator. •
The polarity of the battery, generator, and regulator must be matched and considered before making
any electrical connections within the system.
•
Never operate the alternator on an open circuit. make sure that all connections within the circuit are
clean and tight. •
Disconnect the battery terminals when performing any service on the electrical system. This will
eliminate the possibility of accidental reversal of polarity. •
Disconnect the battery ground cable if arc welding is to be done on any part of the vehicle. •
Alternator
TESTING
General Information
There are many possible ways in which the charging system can malfunction. Often the source of a problem is
difficult to diagnose, requiring special equipment and a good deal of experience. This is usually not the case,
however, where the charging system fails completely and causes the dash board warning light to come on or
the battery to discharge. To troubleshoot a complete system failure, only two pieces of equipment are needed:
a test light, to determine that current is reaching a certain point and a current indicator (ammeter), to
determine the direction of the current flow and its measurement in amps. This test works under three
assumptions:
The battery is known to be good and fully charged. 1.
The alternator belt is in good condition and adjusted to the proper tension. 2.
All connections in the system are clean and tight. 3.
In order for the current indicator to give a valid reading, the vehicle must be equipped with battery
cables which are of the same gauge size and quality as original equipment battery cables.
Before commencing with the following tests, turn off all electrical components on the vehicle. Make sure the
doors of the vehicle are closed. If the vehicle is equipped with a clock, disconnect the clock by removing the
lead wire from the rear of the clock.
Battery No−Load Test
Ensure that the ignition switch is turned OFF. 1.
Connect a tachometer to the engine by following the manufacturer's instructions. 2.
Using a Digital Volt Ohmmeter (DVOM) measure the voltage across the positive (+) and negative (−)
battery terminals. Note the voltage reading for future reference. 3.
Ensure that all electrical components on the vehicle are turned off. Be sure the doors of the vehicle are closed.
If the vehicle is equipped with a clock, disconnect the clock by removing the lead wire from the rear of the
clock.
Start the engine and have an assistant run it at 1500 rpm. 4.
Read the voltage across the battery terminals again. The voltage should now be between 14.1−14.7
volts.
If the voltage increase is less than 2.5 volts over the base voltage measured in Step 3, perform
the Battery Load test. 1.
If there was no voltage increase, or the voltage increase was greater than 2.5 volts, perform
the Alternator Load and No−Load tests. 2.
5.
HOW TO USE THIS BOOK
Alternator Precautions 219