1992 Sierra pickup how to set clock radio

Owners Manual Should have Instructions, I Cannot Locate ANY Such Instructions.
Usualy you Hold the Clock Button and use the Tuner control to change the time.
Below are Some Phone Numbers for TECH Support and Info on User Manuals.
I Hope This HELPS You with your Delima, I have Been there Myself so I Feel your Frustration.

Audio - Procedure To Handle Customer Radio Concerns Notes File In Section: 9 - Accessories
Bulletin No.: 68-96-O1A
Date: October, 1996
INFORMATION
Subject:
Procedure to Handle Customer Radio Concerns
Models:
1997 and Prior Passenger Cars and Trucks
This bulletin is being revised to change the Sales Center Information to
Service Center Information. Please discard Corporate Bulletin Number 68-96-01 (Section 9 - Accessories).
Many of the radios being returned to the Delco Electronics remanufacturing centers have been misdiagnosed. This misdiagnosis results in unnecessary customer comebacks, decreased customer satisfaction and reduces the availability of exchange radios.
To resolve these issues, the following information was developed to give General Motors' dealers a common service process to handle customer audio system concerns.
When a customer either calls or comes in with a concern about the radio system in their vehicle, it is important that as much information as possible is gathered. This process begins with the Service Consultant asking the customer specific questions related to their vehicle as outlined on the Service Writer/Customer Check list.
Once the Service Consultant has completed the diagnostic worksheet, it should be attached to the customer repair order for the technician. This worksheet should help the technician determine if the concern is vehicle related or radio related. Two excellent service manuals are also available for this purpose and are available from General Motors at the address shown below. A service bulletin, 34-92-12, Radio Frequency Interference Diagnosis, is also available as is assistance from the Divisional Technical Assistance Centers.
Mascotech Mktg. Service
1972 Brown Road
Auburn Hills, ML 48326
1-800-393-4831
Delco Electronics Sound Service Audio Systems Diagnostic Guide
P/N 19007.03-1A @ $10.00 per manual
STG Audio Systems Training manual
P/N 19007.03-2 @ $15.00 per manual
Repairs to the vehicle or the audio system can usually be done very quickly and the vehicle returned to the customer that day. If the diagnosis indicates that the radio needs to be replaced, remove the radio from the vehicle and order an exchange radio from your local AC Delco radio exchange center. There are 28 approved AC Delco exchange centers nationally (listing attached). If your local exchange center does not have the required exchange radio, it is important that you contact the AC Delco locator service. This service can be found on the Service Parts TRACS system 1-800-433-6961, prompt 4. It will be necessary to request overnight shipping so that the owner's vehicle is retained at your dealership for only one night.
If the vehicle is kept overnight and it is a warranty repair, the customer should be offered courtesy transportation or alternate transportation. Please do not return the vehicle with the suspect radio installed or without a radio. Many of our vehicles today use a multiplex wiring system and the vehicle will not run correctly without a radio.
When you receive the exchange radio, please return the removed radio to the AC Delco Exchange Center within 24 hours (please enclose the diagnostic worksheet that the Service Consultant and the Technician used with the removed radio along with the 1078 form). This will help the AC Delco Exchange Center.
In the event you know the vehicle will need a radio before the customer brings the vehicle in, every effort should be made to have a pre-exchanged radio available. A radio identification list is attached to help you select the correct radio