Microphone Does Not Work

Microphone Does Not Work

Fault symptoms
Microphone does not work.

Fault diagnosis
Note that the microphone has a high-level and low-level output. Connecting the wrong microphone output can overdrive the unit or give too low a signal level.

Check wiring harness
Jiggle the wiring harness at several points and in different directions to reveal intermittent breaks and short-circuits in the leads. Observe the multimeter, test lamp or diagnostic instrument during the test.





Diagnostic Procedure

1 Checking the leads between the 10-pin connector and microphone.
- Unplug the microphone's 4-pin connector and the 10-pin connector.
- Take a resistance reading across the 10-pin female connector and the microphone's female connector on the following pins:

Pin, 10-pin Connector, microphone
3 2
9 4
10 3

The resistances should be < 1 ohm.
- Take a resistance reading across the pin concerned and a good grounding point.
The resistance should be infinite.

Test results OK?
YES
The fault does not lie in the car wiring.
Continue with point 2.
NO
Repair or replace lead concerned.
Continue with point 3, Final Check.






2 Checking the handsfree unit
- Check the handsfree unit and leads as described by the supplier of the handsfree unit.

Test results OK?
YES
Replace the microphone. Continue with point 3, Final Check.
NO
Repair or replace the handsfree unit. Continue with point 3, Final Check.






3 Final check
- Carry out a function check.
- Evaluate the function check.
- Check that the symptom has not recurred.

Has the symptom recurred?
YES
The cause of the fault lies either in:
1 the leads between the handsfree unit and the microphone.
2 the microphone.
3 the handsfree unit.
Check the above components once again.
NO
The steps taken to rectify the fault were correct.