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Section 2. Automotive Testing
The digital multimeter is a very useful
tool for trouble-shooting automotive elec-
trical systems. This section describes
how to use the digital multimeter to test
the starting and charging system, igni-
tion system, fuel system, and engine
sensors. The digital multimeter can also
be used for general testing of fuses,
switches, solenoids, and relays.
General Testing
The digital multimeter can be used to
test fuses, switches, solenoids, and re-
lays.
Testing Fuses
This test checks to see if a fuse is blown.
You can use this test to check the internal
fuses inside the digital multimeter.
To test Fuses (see Fig. 16):
• If you hear tone - Fuse is good.
• If you don’t hear tone - Fuse is
blown and needs to be replaced.
NOTE: Always replace blown fuses
with same type and rating.
Testing Switches
This test checks to see if a switch
“Opens” and “Closes” properly.
To test Switches (see Fig. 17):
Fig. 17
Red
Typical "Push"
Button Switch
1. Insert BLACK test lead into COM
test lead jack.
2. I n s e r t R E D t e s t l e a d i n t o
test lead jack.
3. Turn multimeter rotary switch to
function.
4. Touch RED and BLACK test leads
together to test continuity.
Listen for tone to verify proper op-
eration.
5. Connect BLACK test lead to one
side of switch.
6. Connect RED test lead to other
side of switch.
Listen for tone:
• If you hear tone - The switch is
closed.
• If you don’t hear tone - The switch
is open.
7. Operate switch.
Listen for tone:
1. Insert BLACK test lead into COM
test lead jack.
2. I n s e r t R E D t e s t l e a d i n t o
test lead jack.
3. Turn multimeter rotary switch to
function.
4. Touch RED and BLACK test leads
together to test continuity.
Listen for tone to verify proper op-
eration.
5. Connect RED and BLACK test
leads to opposite ends of fuse.
Listen for tone:
Fig. 16
Red
Black
Fuse
Black
