The part numbers for the radio affected by this bulletin (as of October 30, 1988) are: 16069272, 16074384, 16122251, 16130743, 16134432, 16070193, 16078051, and 16084242.
If the security is activated and the radio is disconnected from battery power, the radio will display LOC. The radio will not turn on until the correct unlocking code is entered. If the customer's code is lost or unavailable, the procedure to determine the factory back up code and to unlock the radio is listed below. This procedure deactivates the security feature and removes the customer's code from the radio. The radio does not need to be removed from the dash for this procedure. This procedure requires a Touchtone telephone.
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1. Turn the ignition key on.
2. Press and hold "NEXT" and "REV" (presets 2 and 3) .
3. After three seconds digits 1-3 of the radio I.D. number will be displayed. Write them down.
4. Press AM-FM, then digits 4-6 of the radio I.D. number will be displayed. Write them down.
5. Calll-800-537-5140 (U.S. and Canada) or (317) 451-8965.
6. When the computer prompts, enter your dealer code or radio shop account number using a Touchtone telephone, then press *.
7. When prompted, enter the six-digit radio I.D. number from the radio, then press *. The computer will respond with the unlocking code. Write it down. This is the code to unlock the radio.
8. To unlock the radio: A. Turn the ignition on. B. Press "SET" (000 appears on display) . C. Press "SEEK" until the first digit of the code appears. D. Press "SCAN" ("TUNE" on equalizer models) until the second and third digits of the code appear. E. Press AM-FM (000 appears on display). F. Press "SEEK" until the fourth digit of the code appears. G. Press "SCAN" ("TUNE" on equalizer models) until the fifth and sixth digits of the code appear. H. Press AM-FM. Now the radio can be turned on.
9. The radio is now unlocked. To remove the customer's code, the unlocking code must be entered again as in steps 8B through 8H.
General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.