Cellular Telephone Outgoing Calls Hard To Hear (Replace Microphone with a Remote Mounted Microphone)

Some customers may comment that the called party has difficulty hearing the caller when using the cell phone in the hands-free mode.

This condition may be caused by the sound of the air rushing over the windshield. This sound is picked up by the mirror base attachment to the windshield. The mirror mount or pedestal then becomes the sound transmitter, (i.e. a stethoscope) and the microphone then picks up this noise. This noise issue may be reduced considerably using the procedure listed below.

1. Wash hands thoroughly.
2. Remove the trim covers over the moisture sensor and the wiring trim cover from the mirror base to the headliner.
3. Note the routing of the wires to the mirror and the moisture sensor. The wires need to be routed the same way after the repairs.
4. Disconnect the wiring from the mirror and the moisture sensor.
5. Disconnect the upper console from the headliner roof panel by carefully working your fingers between the front edge of the console and the headliner.
6. Disconnect the courtesy lamp wires from the console.
7. With a clean piece of mechanics wire, about 152 mm (6 in) long, form a hook on both ends.
8. Place one hook end of the wire over the passenger side sunshade support and support the upper console with this hook. This will place the console out of the way for additional work area.
9. Gently separate the headliner support and the headliner from the metal roof panel enough to feed/pull the mirror/moisture sensor wires into the console opening in the headliner.
10. Remove the tape wrap of the wiring harness from the moisture sensor wiring breakout to the rose bud retainer about 102 mm (4 in).
11. Inside the opened wiring harness, there is a pair of wires which are wrapped with electrical tape. Carefully remove the tape wrap from these wires (a gray wire and a bare wire).
12. Cut the two wires (the gray wire and the bare wire) as close to the original location of the moisture sensor breakout as possible. This will leave approximately a 102 mm (4 in) length of wire with which to work. Do not cut the wires at the rosebud location.
13. Trim approximately 6 mm (¼ in) of the insulation from the gray wire.
14. Place a 25 mm (1 in) long piece of heat shrink tubing over one of the wires.
15. Carefully and properly crimp terminal number 1216055, (found in the J 38125 Terminal Repair Kit), to each of the cut wires. The overall length of the completed wires must be equal in length.
16. The new microphone has a metal mounting tab that needs to be folded into a "U" clip which will slide over the headliner. Make the bend at the cutout in the mounting tab.
17. Position the microphone wire connector through the cutout in the mounting tab.
18. Slide the new microphone clip between the headliner and the roof panel on the driver's (left) side of the console headliner cutout.
19. Rotate the new microphone on the support clip so that the voice openings face the rear of the vehicle.
20. Connect the new microphone to the reworked wires from Step 15 above. The terminal for the grey wire is to be inserted into the terminal for the red wire. The terminal for the non-insulated wire is to be inserted into the terminal for the blue wire of the microphone wiring connector.
21. Ensure the heat shrink tubing is in position over the terminal of the wire. With a small piece of tape, secure the heat shrink to the wire.
22. Wrap the connector and the wires with electrical tape in order to insulate and remove the possibility of the terminals becoming disengaged from the microphone connector.
23. Carefully and gently separate the headliner support from the roof panel and re-install the mirror and moisture sensor wires into the original locations. Ensure the wires are routed through the cutout of the front edge of the headliner.
24. Re-connect the courtesy lamp wires.
25. Carefully inspect all wires in the headliner opening and ensure the routing of the wires will not be damaged when the console is snapped back into place.
26. Carefully fold the electronic ribbon cable while lifting the console back into position and then snap the console back into position.
27. Re-connect the wiring to the mirror and moisture sensor, ensuring that the wires are properly routed through the openings in the trim covers as they are installed.

Parts are currently available from GMSPO.

For vehicles repaired under warranty, use: