Audio - Background Tone In AM Radio Band
Bulletin 85-9-2Date Nov. '84
Ref. No. 84-338-9
SUBJECT: AUDIBLE BACKGROUND TONE IN AM RADIO BAND
MODELS AFFECTED: ALL 1984 MODELS AND EARLY 1985 ELECTRAS WITH RADIO AND ELECTRONIC CRUISE CONTROL (K34)
An audible background tone usually in the area of 1000 to 1300 on the AM radio band may be noted on some cars. If the tone only occurs with the cruise slide switch in the "ON" position, the cause could be in the cruise module.
FIGURE 1 - CRUISE MODULE:
This condition may be easily diagnosed by turning the ignition to the "ON" position (car not running), move the cruise slide switch to the "ON" position and tune the radio to obtain the interference tone. Once the tone is obtained, if it can be eliminated by moving the cruise slide switch to the "OFF" position, the problem is in the cruise module. Replace the cruise module with a new one with a date code later than 3/1/84. The date code can be found stamped an the label of the cruise module (See Figure 1).