Originally Posted by Maven

Amplifier and Radio pinouts, circuit ID's, color codes:

Audio Amp. Connector1
Connector Part Information
• OEM: 12110088
• 24-Way F Micro-Pack 100 Series (GY)

Pin
Wire Color
Circuit No.
Function

A1
L-GN/BK
1794
Left/Rear Subwoofer Speaker (-)

A2
D-BU/WH
346
Left/Rear Subwoofer Speaker (+)

A3
L-BU/BK
115
Right Rear Speaker Signal (-)

A4
D-BU
46
Right Rear Speaker (+)

A5
BN
199
Left Rear Speaker (+)

A6
YE/BK
116
Left Rear Speaker Signal (-)

A7
D-BU
546
Right Rear Low Level Audio Signal

A8
BN/WH
599
Left Rear Low Level Audio Signal

A9
TN
1946
Right Rear Low Level Audio (-)

A10
BN
1999
Left Rear Low Level Audio (-)

A11
D-GN
117
Right Front Speaker Signal (-) (1)

A12
L-GN
200
Right Front Speaker (+) (1)

B1
L-BU/BK
315
Right Subwoofer Speaker (-)

B2
D-GN
1795
Right Subwoofer Speaker (+)

B3
D-GN
1947
Left Front Low Level Audio (-)

B4
L-GN
1948
Right Front Low Level Audio (-)

B5
TN
511
Left Front Low Level Audio Signal

B6
L-GN/WH
512
Right Front Low Level Audio Signal

B7-B10
--
--
Not Used

B11
GY
118
Left Front Speaker Signal (-) (1)

B12
TN
201
Left Front Speaker (+) (1)



Audio Amplifier Connector2 (UQ3)
Connector Part Information
• OEM: 12110626
• 8-Way F Metri-Pack 280 Series (L-GY)

Pin
Wire Color
Circuit No.
Function

A
BK/WH
1051
Signal Ground

B
BK/WH
1051
Signal Ground

C
--
--
Not Used

D
L-GN
1011
Remote Radio Control Signal

E
PK
314
Radio On Signal

F
--
--
Not Used

G
RD/WH
640
Battery Positive Voltage

H
RD/WH
640
Battery Positive Voltage




Radio C1



Connector Part Information
• OEM: 12110206

• Service: See Catalog

• 24-Way F Micro-Pack 100 Series (L-BU)

Pin
Wire Color
Circuit No.
Function

A1
GY
118
Left Front Speaker Signal (-) (1) (U1C)

A1
D-GN
1947
Left Front Low Level Audio (-) (US8)

A2
TN
201
Left Front Speaker (+) (1) (U1C)

A2
TN
511
Left Front Low Level Audio Signal (US8)

A3
L-BU
115
Right Rear Speaker Signal (-) (U1C)

A3
TN
1946
Right Rear Low Level Audio (-) (US8)

A4
D-BU
46
Right Rear Speaker (+) (U1C)

A4
D-BU
546
Right Rear Low Level Audio Signal (US8)

A5
BN
199
Left Rear Speaker (+) (U1C)

A5
BN/WH
599
Left Rear Low Level Audio Signal (US8)

A6
YE
116
Left Rear Speaker Signal (-) (U1C)

A6
BN
1999
Left Rear Low Level Audio (-) (US8)

A7
L-GN
200
Right Front Speaker (+) (1) (U1C)

A7
L-GN/WH
512
Right Front Low Level Audio Signal (US8)

A8
D-GN
117
Right Front Speaker Signal (-) (1) (U1C)

A8
L-GN
1948
Right Front Low Level Audio (-) (US8)

A9
D-BU
1796
Steering Column Radio Control Signal (UK3)

A10
WH/BK
644
10-Volt Reference (US8)

A11
--
--
Not Used

A12
BK/WH
1051
Signal Ground

B1
RD/WH
1140
Battery Positive Voltage

B2
--
--
Not Used

B3
L-GN
1011
Remote Radio Control Signal (US8)

B4-B5
--
--
Not Used

B6
PK
314
Radio On Signal

B7-B8
--
--
Not Used

B9
D-GN
5060
Low Speed GMLAN Serial Data

B10-B12
--
--
Not Used



Radio Connector2
Connector Part Information
• OEM: 12064799
• 12-Way F Micro-Pack 100 Series (BK)

Pin
Wire Color
Circuit No.
Function

A-G
--
--
Not Used

H
D-GN/WH
368
Right Audio Signal (+)

J
BN/WH
367
Left Audio Signal (+)

K
TN/WH
372
Audio Common

L
OG/BK
2061
Cellular telephone voice Low Reference (UE1)

M
PK/BK
2062
Cellular Telephone Voice Signal (UE1)


relevant RPO descriptions:

UK3
Control, Steering Wheel, Accessory

UN0
Radio, AM/FM Stereo, Seek/Scan, CD, Auto Tone, Clock, ETR

UQ3
Speaker System, Performance Enhanced Audio

UQ4
Speaker System, 4, Base

US8
Radio, AM/FM Stereo, Seek/Scan, CD, Auto Tone, Clock, ETR, MP3, RDS

U1C
Radio, AM/FM Stereo, Seek/Scan, CD, Clock, ETR

U2K
Digital Audio System S-Band

UE1
Communication System, Vehicle, G.P.S. 1


the radio DOES communicate on the Lowspeed GM-LAN line, it recieves VIN information for TheftLok, illumination dimming inputs, and signal for speed compensated volume.

Some audio functions are available using the steering wheel controls. The steering wheel controls are actually a resistor network which consists of multiple momentary contact switches and a series of resistors. The switches and resistor network is arranged so that each switch has a different resistance value. When a switch is pressed, a voltage drop occurs in the resistor network which produces a specific voltage value unique to the switch selected. These specific voltage values allow the radio to identify which switch has been pressed. The radio responds just as if the corresponding radio front panel button had been pressed.When the radio is ON, the radio supplies approximately 10 volts to the switches on the 10-volt reference circuit. The specific voltage signal from the switch is returned to the radio on the steering wheel controls signal circuit.This may inhibit the use of the redundant control with an aftermarket head unit.

(Gm Service Information 2005 Chevrolet Cobalt)


Some of you may have been aware of this information, many of you may not have, hope it helps any who need it.
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