GM Service Manual Online
For 1990-2009 cars only
Table 1: C1 -- Automatic Transfer Case (ATC) Control Module
Table 2: Automatic Transfer Case (ATC) Control Module C2
Table 3: Automatic Transfer Case (ATC) Select Switch C-1
Table 4: Automatic Transfer Case (ATC) Select Switch C-2
Table 5: Transfer Case -- Encoder Motor -- C-1
Table 6: Transfer Case -- Encoder Motor -- C-2

C1 -- Automatic Transfer Case (ATC) Control Module


Object Number: 73221  Size: CH

Connector Part Information

    • 12052107
    • 32 Way F Micro-Pack 100 Series (ORN)

Pin

Wire Color

Circuit No.

Function

E1

TAN

1569

Transfer Case Lock Solenoid Output

E2

--

--

Not Used

E3

PNK

1561

S4WD Indicator Lamp Output

E4

LT GRN/BLK

1563

2 HI Indicator Lamp Output

E5

BRN/WHT

1555

Transfer Case Position Switch Encoder Signal (Channel P)

E6

RED/WHT

1556

Transfer Case Position Switch Encoder Signal (Channel C)

E7

YEL/BLK

1558

Transfer Case Position Switch Encoder Signal (Channel B)

E8

DK BLU/WHT

1557

Transfer Case Position Switch Encoder Signal (Channel A)

E9

DK GRN/WHT

1133

Serial Data Signal - Class 2

E10

BRN

241

Fused Ignition 3 Feed

E11

--

--

Not Used

E12

YEL

400

Vehicle Speed Sensor Signal

E13

PPL

401

Vehicle Speed Sensor Return

E14

BLK/WHT

1695

Four Wheel Drive Front Wheel Lock Telltale Feed

E15

--

--

Not Used

E16

BLK

1850

Ground

F1

PPL/WHT

1565

4 LO Indicator Lamp Output

F2

TAN/BLK

1566

4 HI Indicator Lamp Output

F3

BRN

1560

Neutral Indicator Lamp Output

F4

LT BLU

1296

Four Wheel Drive Relay Feed - Coil

F5

LT BLU

2221

Vehicle Speed Sensor Signal

F6

DK GRN

2222

Vehicle Speed Sensor Return

F7

GRY/BLK

1694

Four Wheel Drive Switch Signal - Low

F8 - F11

--

--

Not Used

F12

BLK/WHT

1554

Transfer Case Encoder Switch Signal

F13

LT GRN/BLK

431

Reference Voltage Feed - 8 Volts

F14

LT GRN/BLK

431

Reference Voltage Feed - 8 Volts

F15

--

--

Not Used

F16

LT BLU

1693

Four Wheel Drive Switch Signal

Automatic Transfer Case (ATC) Control Module C2


Object Number: 62450  Size: CH

Connector Part Information

    • 12052856
    • 4 Way F Metri-Pack 280 Series (BLK)

Pin

Wire Color

Circuit No.

Function

A

BLK

1552

Transfer Case Motor Feed - Clockwise

B

RED

1553

Transfer Case Motor Feed - Counterclockwise

C

BLK

2150

Ground

D

ORN

1640

Fused Battery Feed

Automatic Transfer Case (ATC) Select Switch C-1


Object Number: 130635  Size: CH

Connector Part Information

    • 12045813
    • 4 Way F Metri-Pack 150 (NAT)

Pin

Wire Color

Circuit No.

Function

A

LT GRN/BLK

431

Reference Voltage Feed - 8 Volt Reference

B

LT GRN/BLK

1563

2 HI Indicator Lamp Output

C

PPL/WHT

1565

4 LO Indicator Lamp Output

D

TAN/BLK

1566

4 HI Indicator Lamp Output

Automatic Transfer Case (ATC) Select Switch C-2


Object Number: 39746  Size: CH

Connector Part Information

    • 12064862
    • 8 Way F Metri-Pack 150 Series (BLK)

Pin

Wire Color

Circuit No.

Function

A

BLK

1850

Ground

B

PNK

1561

Indicator Lamp Output (Auto 4WD)

C

BRN

1560

Indicator Lamp Output (Neutral)

D

--

--

Not Used

E

PPL/WHT

1382

LED Dimming Signal

F

GRY

8

Instrument Panel Lamp Feed

G

PNK

39

Fused Ignition 1 Feed

H

LT BLU

1693

ATC Select Switch Signal

Transfer Case -- Encoder Motor -- C-1


Object Number: 365977  Size: CH

Connector Part Information

    • 12191399
    • 4 Way F Metri-Pack 280 Series (BLK)

Pin

Wire Color

Circuit No.

Function

A

BLK

1552

Transfer Case Motor Feed - Clockwise

B

RED

1553

Transfer Case Motor Feed - Counterclockwise

C

ORN

1640

Fused Battery Feed

D

TAN

1569

Transfer Case Lock Solenoid Output

Transfer Case -- Encoder Motor -- C-2


Object Number: 62449  Size: CH

Connector Part Information

    • 12052848
    • 6 Way M Metri-Pack 150 Series (BLK)

Pin

Wire Color

Circuit No.

Function

A

BLK/WHT

1554

Transfer Case Encoder Signal Return

B

DK BLU/WHT

1557

Transfer Case Postion Switch Encoder Signal - Channel A

C

RED/WHT

1556

Transfer Case Postion Switch Encoder Signal - Channel C

D

YEL/BLK

1558

Transfer Case Postion Switch Encoder Signal - Channel B

E

LT GRN/BLK

431

Reference Voltage Feed - 8 Volt

F

BRN/WHT

1555

Transfer Case Postion Switch Encoder Signal - Channel P