Pontiac Fiero 1988 Service Manual page 939

TROUBLESHOOTING T E S T S
TESTING FOR VOLTAGE DROP
This test checks for voltage being lost along
a wire, or through a connection or switch.
1. Connect the positive lead of a voltmeter to
the end of the wire (or to one side of the con-
nection or switch) which is closer to the Bat-
tery.
2. Connect the negative lead to the other end
of the wire (or the other side of the connec-
tion or switch).
3. Operate the circuit.
4. The voltmeter will show the difference in
voltage between the two points. A dif-
ference (or drop) of more than one volt indi-
cates a problem.
H O T A T A L L T I M E S
SWITCH
S O L E N O I D
Voltage Drop Test
TESTING FOR SHORT TO
GROUND
With a Test Light or Voltmeter
1. Remove the blown fuse and disconnect the
load.
2. Connect a test light or voltmeter across the
fuse terminals (be sure that the fuse is
powered).
3. Beginning near the fuse block, wiggle the
harness from side to side. Continue this at
convenient points (about 6 inches apart)
while watching the test light or voltmeter.
4. When the test light glows, or the voltmeter
registers, there is a short to ground in the
wiring near that point.
HOT AT ALL TIMES-
FUSE
B L O C K
(FUSE
R E M O V E D )
^ SHORT TO
'IF
GROUND
A
R E D
SWITCH
BLU
LOAD
D I S C O N N E C T E D
SOLENOID
T e s t i n g
For Short With Test Light
or Voltmeter
With a SeSf-Powered Test Light or Ohmmeter
1. Remove the blown fuse and disconnect the
battery and load.
2. Connect one lead of a self-powered test light
or ohmmeter to the fuse terminal on the
load side.
3. Connect the other lead to a known good
ground.
4. Beginning near the fuse block, wiggle the
harness from side to side. Continue this at
convenient points (about 6 inches apart)
while watching the self-powered test light or
ohmmeter.
5. When the self-powered test light glows, or
the ohmmeter registers, there is a short to
ground in the wiring near that point.
BATTERY DISCONNECTED
T
jjLOAD
7 D I S C O N N E C T E D
S O L E N O I D
Testing For Short With Self-Powered
Test Light or Ohmmeter