Urrea UD88 User's Manual And Warranty Information page 74

E N G L I S H
Disable the ignition so the engine doesn't start and
crank the engine for 4 ~ 5 seconds.
If the starter turns the engine slowly, the current draw
is not high, and the battery is in good condition, check
the resistance (or voltage drop) in the starter circuit
again.
Charging System Tests
Charging system problems often are identified with a
No-Start complaint. The battery will have discharged
and the starter won't crank the engine. To properly
check the charging system, it must be fully charged.
To diagnose and adjust regulators/alternators, on
a typical GM vehicle, you must first determine if
the system has an integral (internal) regulator, then
whether it is a type A or B alternator.
The type A alternator has one brush connected to the
battery (+) and the other brush grounded through the
regulator. The type B regulator has one brush tied to
Ground and the other connected to the battery (+)
through the regulator. Next isolate the problem to
either the alternator or regulator. To do this you need
to by-pass the regulator (this is called "Full Fielding"),
Ground the type A field terminal, or connect the type
B field terminal to the battery (+) side. If the system
now charges, the regulator is faulty.
CAUTION: WHEN PERFORMING THIS TEST, IDLE THE
ENGINE WITH THE LIGHT ON SO THE OUTPUT VOLTAGE
DOES NOT GO OVER 15V. CHECKING AN ALTERNATOR
WITH AN INTEGRAL REGULATOR, YOU MUST KNOW WHICH
TYPE YOU ARE TESTING TO AVOID ANY DAMAGE TO THE
ALTERNATOR OR REGULATOR.
1. Alternator Output Voltage Test at the Battery
(+)
This test checks for alternator output voltage at the
battery.
To measure alternator output voltage:
- Set the rotary switch to voltage ( ).
- Turn all vehicle accessories off.
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Connect:
- Black lead to the negative (-) battery post.
- Red lead to the positive (+) battery post.
Set:
- RECORD (MAX-MIN-AVG) function on the Meter.
Start the engine and run it at 2000 RPM. A reading of
13.5-15.5V is an acceptable charging rate.
If the voltage is low, check for:
- Defective alternator or regulator.
- Cracked, glazed or loose drive belt.
- Faulty or loose wires or connectors.
2. Alternator Output (+) Voltage Test (Loaded)
This test is necessary only if the vehicle failed the
above test.
To measure alternator output voltage:
- Set the rotary switch to voltage ( ).
- Set up the (MAX-MIN-AVG) function on the Meter.
Connect:
- Black test probe to the negative (-) battery post.
- Red test probe to the battery (+) terminal on the
back of the alternator.