HOW TO DIAGNOSE
GENERAL 00E-4
INSPECTIONM1001004600139
1. Sight and sound checks
Check relay operation, blower motor rotation, light
illumination, etc. Listen for a "click" when some relay covers
are pushed down.
2. Simple checks
For example, if a headlight does not come on and a faulty
fuse or poor grounding is suspected, replace the fuse with a
new one. Or use a jumper wire to ground the light to the
body. Determine which part(s) is/are responsible for the
problem.
3. Checking with instruments
Use an appropriate instrument in an adequate range and
read the indication correctly.
CHARGING SYSTEM
ENGINE ELECTRICAL16-12
NOTE: The voltage waveform of the alternator "B" terminal can
undulate as shown at left. This waveform is produced when the
regulator operates according to fluctuations in the alternator
load (current), and is normal for the alternator.
If the ripple height is abnormally high (approximately 2 V or
more during idling), the wires between the alternator "B" termi-
nal and the battery have broken due to fuse blowing, etc. The
alternator is usually operating properly.
.
ABNORMAL WAVEFORMS EXAMPLES
NOTE: The size of the waveform patterns can differ greatly,
depending on the adjustment of the variable knob on the oscil-
loscope.
NOTE: Identification of abnormal waveforms is easier when
there is a large output current (regulator is not operating).
(Waveforms can be observed when the headlights are illumi-
nated.)
NOTE: Check the conditions of the alternator malfunction light
(illuminated/not illuminated) also, and carry out a total check.
ABNORMAL WAVEFORMS
Example 1
PROBABLE CAUSE: Open circuit in diode
