AM Radio - Noise & Reception Problems

9233mazda01

Bulletin No. 009/92
Issued 4/7/92


Category
T


Applicable Model/s
1991 Navajo


Subject:
AM RADIO
NOISE & RECEPTION PROBLEMS


DESCRIPTION

Static, station fading or engine noise interference on weak to moderate strength AM radio stations may be caused by the auto cruise control unit, or a faulty in-line connector for the antenna.

If the vehicle was built prior to February 28, 1991, the problem may be corrected by installing the new cruise control unit. This unit has been installed at production since February 28, 1991.

NOTE:
The following diagnostic procedures assume that during your test/validation process you have concluded that this symptom is abnormal and not related to a defective radio or antenna mast.


VIN OF PRODUCTION CHANGE

4F2CU44X*MUM00001 - MUM11993 February 28, 1991


DIAGNOSTIC PROCEDURES





Auto Cruise Control Unit

Validate the problem by operating the vehicle using all cruise control functions. If static or fading occurs only when the cruise control is activated, and the vehicle was produced prior to February 28, 1991, the auto cruise control unit should be replaced with the new part.

If static, fading, or engine interference noise continues regardless of cruise control operation, it is possible that the in-line connector is causing the problem and should be replaced.





In-Line Cable Connector

Before replacing the in-line connector, perform the following:

1. Inspect cable connector at antenna base for corrosion. If corroded, clean with steel wool and remove steel wool particles.

2. Apply white lithium grease to female end of connector.

3. Retest.

4. If problem is still present, check in-line cable connector behind glove box for corrosion.

5. If corroded, clean cable ends as described in step 1.

6. Replace in-line cable connector (ZZL0 66 931) and reconnect cables.


7. Retest.

8. If problem is still present, replace antenna cables.

NOTE:

Be sure cables are routed away from blower motor. Blower motors can be a source of static.


PARTS INFORMATION

PART NUMBER DESCRIPTION

ZZL0 66 320A Speed Control Module

ZZL0 66 931 In-Line Cable Connector

ZZLO 66 970 Antenna Cable


WARRANTY INFORMATION

(applies to vehicles covered under warranty)

Auto Cruise Control Unit

Warranty Type Code: A
Customer Comment Code: B2
Damage Code: AB
Part No. of Main Cause: ZZL0 66 320A
Quantity: 1
Operation No: T0804XRX
Labor Hour: 0.2 Hr.

In-Line Cable Connector

Warranty Type Code: A
Customer Comment Code: B2
Damage Code: AA
Part No. of Main Cause: ZZL0 66 970
Quantity: 1

Operation No/Labor Hour:
1. Inspect and clean cable behind glove box YY0042RX / 0.2 Hr.
2. Inspect and clean cable at base of antenna YY0043RX / 0.3 Hr.
3. Replace both antenna cables YY0044RX / 0.9 Hr.