The purpose of the following procedure is to demonstrate how to
check for a short circuit between multiple circuits.
NOTE:
The circuit shown
is an example, and is intended for demonstrational purpose only.
The following are circuit tests covered in this procedure:
Testing For A Short
Between Multiple Circuits
NOTE:
Perform the
following test using a known good multimeter.
Below is a list of possible causes that could be related to a Multiple
Short condition.
Possible Causes
SHORTED CIRCUIT (CHAFED, PIERCED OR PINCHED WIRES)
SHORTED IN-LINE CONNECTOR
(BENT, PUSHED OUT OR CORRODED TERMINALS)
TESTING FOR
A SHORT BETWEEN MULTIPLE CIRCUITS
NOTE:
Before measuring the
resistance of any circuit, first measure the resistance between the
two leads of the multimeter. Take this value and subtract it from
the value recorded when measuring the resistance of the circuit being
checked (The meter leads can add 0.5 ohm or more of total resistance).
1.
Turn the ignition
off.
2.
Disconnect the
wire harness connectors of the components that contain the circuits
that are suspected of being shorted together.
NOTE:
Check connectors -
Clean/repair as necessary.
3.
At this time leave
all in-line connectors connected.
4.
With all the component
wire harness connectors disconnected, use a multimeter set to Ohms
(Ω), and measure the resistance between the applicable circuits in
one of the harness connectors.
5.
Use one lead of
the multimeter and carefully probe the circuit suspected of being
shorted.
6.
Use the other lead
of the meter and one at a time, carefully probe the other circuits
in the harness connector.
Is the
resistance below 10k ohms when probing any two circuits?
Yes
Repair the short between
the circuits. Use the wiring diagram as a guide to trace the circuits
and look for any in-line connectors where the short could occur.
One method to help
isolate the short is to disconnect any in-line connectors that the
circuit being tested runs through and measure for the short again.
If the short goes away, the short is on the other side of the in-line
connector.
No
The circuit is not
shorted or the condition that originally caused the short may not
be present at this time. Continue to measure the resistance and wiggle
the wire harness and connectors while checking for an intermittent
short.
NOTE:
By
disconnecting the wire harness connectors you may have eliminated
the source that was causing the short.
Use the wiring diagram
as a guide to trace the circuits and look for any in-line connectors
where the short could occur intermittently.
Look for any chafed,
pierced, pinched, or partially broken wires.
Look for broken, bent,
pushed out or corroded terminals. Verify that there is good pin to
terminal contact in the related wire harness connectors.
Perform any Technical
Service Bulletins (TSBs) that may apply.
