Radio - Interference On the AM Band

CATEGORY
Electrical

SECTION
3

PAGE
94

ISSUE
06/96-0692

CODE
931

Subject:
Correcting a Customer Complaint of AM Radio Interference

Application:
1994-1996 900

Supersedes 06/96-0691

To correct customer complaints of AM radio interference on 1994-1996 900 models, it may prove necessary to install extra grounding straps on the vehicle. Be sure that the ignition cables, and the antenna and antenna cable are in good condition first. Perform an engine ground voltage drop test with the electrical system under load. If there is a voltage drop greater than 0.1 V, replace the engine ground cable. Then follow the directions below to correct this complaint.

Cars Affected:

1994-1996 900 models

Parts:

16" bonding strap such as NAPA/Belden 711699 (3) [sourced locally]

8" bonding strap such as NAPA/Belden 710899 (1) [sourced locally]

8 mm x 13 mm bolt (1) [sourced locally]

8 mm lock washer (1) [sourced locally]

Clip Nut (1) 86 01 916

Hexagon screw (1) 79 83 000

Speed clip with screw (1) [sourced locally]

Black 14 gauge wire [sourced locally]

Terminal 91 20 957

Ring terminal (1) for 14 gauge wire [sourced locally]

Ring terminal (1) for 10 gauge wire [sourced locally]

Action:

1. Raise the car on a lift.

2. Using a 10 mm nut, secure one end of a 16 in. braided ground strap to the main battery ground at the transmission.

Note:
Do not wrap the ground strap around the A/C suction pipe. If you have done so to any car in the past, please correct the routing the next time that car is returned for service.

Remove one of the screws securing the lower left spoiler panel and attach the loose end of the ground strap to between the panel and the engine subframe using the original screw.

3. Attach a second 16" braided ground strap to the threaded cast iron boss on the engine block near the oil filter and oxygen sensor. Use a 8 x 1 .25 mm bolt, 13 mm long, and a star washer.

Remove one of the screws securing the right lower spoiler panel and attach the other end of the ground strap between the panel and the engine subframe using the original screw.

4. Attach an 8" braided strap to the 8 mm bolt of the exhaust clamp just behind the catalytic converter. Install a speed clip into the available rectangular hole just to the left of center on the rear edge of the engine subframe.

Secure the loose end of the strap to the subframe using a sheet metal screw.

5. Lower the vehicle to the ground.

6. Attach the third 16" braided ground strap under the T40 Torx screw on the driver's side end of the cylinder head. Secure the loose end under the left-hand 6mm bolt that holds the strut tower brace to the firewall.

7. Remove the gray connector at the rear of the radio.

Remove the black ground wire terminal 8 from the gray connector and tape the wire back to the harness.

Install a new terminal, P/N 91 20 957, on a length of 14 gauge black wire. Insert the terminal into the connector and reinstall the connector.

8. Premium sound systems only: remove the wire at terminal 1 of the 2-pin amplifier connector. Cut the wire end off and tape it back to the harness.

Install a new wire end, P/N 91 20 791, onto a length of 14 gauge black wire. Insert the wire end into terminal 1 of the 2-pin connector.

9. Attach the loose ends of the wires added in steps 7 and 8 to the ring terminal (for 14 gauge wire). Secure the ring connector to the main ground point at the right A-pillar.

10. From the end of the antenna coaxial cable nearest the antenna, measure back 13 in.

Cut out approximately 1 in. of insulation to expose the shielded cable.

Spread open a ring terminal (for 10 gauge wire), place it around the bare shielded cable, and clamp the ring terminal closed.

Verify that the antenna motor is properly grounded.

Secure the ring terminal to the antenna motor bracket.

If an AM radio interference problem persists or for any clarification regarding these procedures, contact the Technical Assistance Center at 1-800-766-2857.

Warranty Information:

To resolve a customer complaint for a vehicle in warranty, submit a claim using the following information:

Failure code: 36742-63-0-01-05

Labor operation number: 36749 for 1.2 hours.

Please update your DOS operation number tables using the following information:

Operation: 36749
Trans Type: B
Engine Type: 9
Diag. Reqd: 0
Model: M94 900 only
Hours: 1.2
Begin Yr. 94
End Yr. 96