Step  | Action  | Value(s)  | Yes  | No  | 
|---|---|---|---|---|
Schematic Reference: OnStar Schematics Connector End View Reference: Component Connector End Views  | ||||
1  | Did you perform the Diagnostic System Check - Vehicle?  | --  | Go to Step 2  | |
2  | 
 Is the radio reception clear?  | --  | Go to Step 3  | |
3  | 
 Did you find and correct the condition?  | --  | Go to Step 18  | Go to Step 4  | 
4  | Does poor or no reception occur only on AM?  | --  | Go to Step 5  | Go to Step 6  | 
5  | 
 Does the voltage measure near the specified value?  | 12 V  | Go to Step 6  | Go to Step 9  | 
6  | 
 Important: Always zero out the DMM before taking a resistance measurement to ensure an accurate reading. Does the resistance measure greater than the specified value?  | 0.20 Ω  | Go to Step 10  | Go to Step 7  | 
7  | 
 Important: Always zero out the DMM before taking a resistance measurement to ensure an accurate reading. 
 Does the resistance measure greater than the specified values?  | RG-58/RG-59 Coax: 0.20 Ω RG-62/RG-62M Coax: 3.5 Ω  | Go to Step 11  | Go to Step 8  | 
8  | 
 Did you measure continuity?  | --  | Go to Step 15  | Go to Step 12  | 
9  | Test the antenna relay coil voltage circuit for an open, short to ground or high resistance. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?  | --  | Go to Step 18  | Go to Step 13  | 
10  | Test the antenna amplifier module case ground for an open or high resistance. Refer to Circuit Testing . Did you find and correct the condition?  | --  | Go to Step 18  | Go to Step 14  | 
11  | Inspect the antenna coaxial cable interconnects for a poor connection or corrosion. Refer to Testing for Intermittent Conditions and Poor Connections . Did you find and correct the condition?  | --  | Go to Step 18  | Go to Step 15  | 
12  | Inspect for poor connections at the antenna amplifier module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition?  | --  | Go to Step 18  | Go to Step 16  | 
13  | Inspect for poor connections at the radio. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition?  | --  | Go to Step 18  | Go to Step 17  | 
14  | Test for an open or high resistance from the negative battery cable to body ground. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?  | --  | Go to Step 18  | Go to Step 11  | 
15  | Replace the antenna coaxial cable. Did you complete the replacement?  | --  | Go to Step 18  | --  | 
16  | Replace the antenna amplifier module. Did you complete the replacement?  | --  | Go to Step 18  | --  | 
17  | 
 Important:: Perform the setup procedure after replacing the radio. Replace the radio. Refer to Radio Replacement . Did you complete the replacement?  | --  | Go to Step 18  | --  | 
18  | Operate the system in order to verify the repair. Did you correct the condition?  | --  | System OK  | Go to Step 2  |