Check for continuity between Hands Free Telephone control unit 28P connector terminal No. 13 and microphone 3P connector terminal No. 1.
Is there continuity?
YES
-
Substitute a known-good Hands Free Telephone control unit, then recheck. If the symptom goes away, replace the original
Hands Free Telephone control unit
.■
NO
-
Replace the faulty harness between the Hands Free Telephone control unit and the microphone.■