Radio - Ignition Noise Heard Over the Speakers
Bulletin No.:T-93-61
File in Group:
9
Number:
93
Corp.Ref.No.:
319601
Date:
Feb. 1993
SUBJECT:
IGNITION NOISE AUDIBLE OVER BOSE RADIO SPEAKERS
MODELS AFFECTED:
1993 ELDORADOS AND SEVILLES EQUIPPED WITH BOSE RADIO AND NORTHSTAR (OPTION CODES U1G AND L37/LD8)
Some 1993 Eldorados and Sevilles built before breakpoints 607486 and 813446 and equipped with both the Northstar powertrain (L37 or LD8) and the Bose radio (U1G) options may experience a noise condition over the radio speakers that may be described as a "ticking", "crackling", "buzzing", or "static" noise that usually occurs at engine idle and at low volume settings. The noise is primarily heard over the front speakers and will occur in all audio modes: AM, FM, CD, and tape. The noise condition may not be present at engine speed greater than 1500 rpm.
This condition may be caused by insufficient suppression within the Bose amplifiers located inside the speaker enclosures. A new amplifier is available to correct this condition. To determine if the cause of the noise is due to insufficient suppression within the amplifiers, use the following diagnosis procedure:
1. Turn all accessories to the "OFF" position. With the key "ON" and engine "OFF", turn the radio to the minimum volume setting.
2. If the noise is heard, refer to Section 9A of the 1992 Eldorado and Seville Service Information Manual for diagnosis.
3. Start engine.
4. If the noise is heard, determine which speakers exhibit the condition.
To repair this condition replace the amplifiers of the speaker pair that exhibits the noise. Amplifiers of the speakers must be replaced in pairs (both fronts or both rears). For example; if the right front speaker exhibits the condition, then both left and right front speaker amplifiers must be replaced. Refer to the 1992 Eldorado and Seville Service Information Manual, Section 9A, for the replacement procedure. The amplifier part numbers are:
Front Rear
Seville: 16188340 16188341
Eldorado: 16188338 16188339
Parts are expected to be available on February 22, 1993.
Warranty Information