| Connector "A" | ||
| Contact | Function | Type |
| 1 | +Battery | Power |
| 2 | Ground | Ground |
| 3 | Control Solenoid | Output |
| 4 | Supply Solenoid | Output |
| 5 | Retarder Lamp | Output |
| 6 | Unused | - |
| 7 | Unused | - |
| 8 | Unused | - |
| 9 | Unused | - |
| 10 | Engine Speed | Frequency Sensor Input |
| 11 | ON | Switch Input |
| 12 | Engine Oil Pressure | Switch Input |
| 13 | Accelerator Pressure | Switch Input |
| 14 | Unused | - |
| 15 | Unused | - |
| 16 | Auto Retarder Pressure | Switch Input |
| 17 | Harness Code 2 | Switch Input |
| 18 | Harness Code 1 | Switch Input |
| 19 | Harness Code 0 | Switch Input |
| 20 | Unused | - |
| 21 | Retarder Pressure | Switch Input |
| 22 | Unused | - |
| 23 | Unused | - |
| 24 | Unused | - |
| 25 | Unused | - |
| 26 | Unused | Switch Input |
| 27 | Unused | - |
| 28 | Unused | - |
| 29 | Unused | - |
| 30 | Unused | - |
| 31 | Unused | - |
| 32 | Unused | - |
| 33 | Unused | - |
| 34 | Unused | - |
| 35 | Unused | - |
| 36 | Harness Code 4 | Switch Input |
| 37 | Harness Code 3 | Switch Input |
| Connector "B" | ||
| Contact | Function | Type |
| 1 | Unused | - |
| 2 | Unused | - |
| 3 | Unused | - |
| 4 | Unused | - |
| 5 | Unused | - |
| 6 | Set | Switch Input |
| 7 | Clear | Switch Input |
| 8 | Unused | - |
| 9 | Data Link + | Input/Output |
| 10 | Data Link - | Input/Output |
 | |
| Illustration 1 | g00326965 |
(1) Connector "B" (2) Connector "A" (3) Digital display | |
Electronic circuits and software within the Automatic Retarder Control (ARC) determine the actions of the ARC. Connector "B" (1) and connector "A" (2) join the harness wiring to the inputs of the ARC and to the outputs of the ARC. Digital display (3) shows diagnostic information for troubleshooting the ARC.
The ARC continuously monitors the conditions that are pertinent to retarding. Components sense these conditions and electrical signals are sent to the ARC. The ARC compares the information from the electrical signal to the information that is stored in memory. From this comparison, the ARC determines the proper action. After the ARC retards the machine, electrical signals are sent from the ARC to the supply solenoid and to the control solenoid.
The same ARC can be used on different machines. The ARC recognizes the type of machine by the machine's harness code.
Numerous inputs inform the ARC of the conditions of the machine. The ARC has two types of inputs: switch inputs and sensor inputs. Switches and harness wiring provide an open signal, a ground signal or a +battery signal to the switch inputs. Sensors provide a constantly changing signal to the sensor inputs.
The ARC responds to the incoming signals by sending electrical signals through various outputs. The outputs create an action or the outputs provide information.
The data link is used to communicate with other electronic control modules on the machine. Because the data link is bidirectional, the ARC can receive information and the ARC can send information.