Testing for Electrical Intermittents
Special Tools
EL-39200 Digital Multimeter
For equivalent regional tools, refer to
Special Tools .
Perform the following procedures while wiggling the harness from
side to side. Continue this at convenient points (about 6 inches
apart) while watching the test equipment.
If the fault is not identified, perform the procedure below
using the MIN MAX feature on the EL-39200 digital
multimeter(DMM). This feature allows you to manipulate the circuit
without having to watch the DMM . The DMM will generate an audible
tone when a change is detected.
Note: The DMM must be used
in order to perform the following procedure since the DMM can
monitor current, resistance or voltage while recording the minimum
(MIN), and maximum (MAX) values measured.
| 1. |
Connect the DMM to both sides
of a suspected connector (still connected), or from one end of a
suspected circuit to the other. Refer to
Troubleshooting with a Digital Multimeter for information on
connecting the DMM to the circuit. |
| 2. |
Set the DMM to the V (AC) or V
(DC) position. |
| 3. |
Select the voltage range
feature of the DMM in order to select the desired voltage
range. |
|
Note: The 100 ms
RECORD mode is the length of time an input must stay at a new value
in order to record the full change.
|
| 4. |
Select the MIN MAX function of
the DMM. The DMM displays the 100 ms RECORD and emits an
audible tone (beep). |
| 5. |
Simulate the condition that is
potentially causing the intermittent connection, either by wiggling
the connections or the wiring, test driving, or performing other
operations. Refer to
Inducing Intermittent Fault Conditions . |
| 6. |
Listen for the audible Min Max
Alert which indicates that a new minimum or maximum value has been
recorded. |
| 7. |
Press the MIN MAX button until
the MAX value is displayed and note the value. |
| 8. |
Press the MIN MAX button until
the MIN value is displayed and note the value. |
| 9. |
Determine the difference
between the MIN and MAX values. |
| |
• |
If the variation between the
recorded MIN and MAX voltage values is 1 V or greater an
intermittent open or high resistance condition exists. Repair the
condition as necessary. |
| |
• |
If the variation between the
recorded MIN and MAX voltage values is less than 1 V, an
intermittent open or high resistance condition does not
exist. |
|
