| Connector Pin | Circuit Number | Circuit Usage |
| A | 75 | Stop Lamp Switch. Runs through brake light switch to Pin K. |
| B | 40 | Panel/Instrument Lights. |
| C | 22 | Stop Lights. Hot when brakes applied. Runs to turn signal switch if used. |
| D | 19 | Black Out Driving Lamp. |
| E | 20 | Black Out Marker and Taillamps. |
| F | 15 | Battery Power Lead. |
| H | 21 | Service Taillamps. |
| J | 467 | To flasher switch. Hot when stop or head lights on. |
| K | 75 | Stop Lamp Switch. Runs from pin A through brake light switch. |
| L | 491 | Parking Lights (if used). |
| M | 16 | Service Headlamps. To dimmer switch or headlight relay. |
| N | 23 | Black Out Stop Lamp. |
M-Series Trailer Receptacle Pinout
| Connector Pin | Circuit Number | Circuit Usage |
| A | 24A | Blackout Tail Light |
| B | 22 | Stop Lamp |
| C | 24B | Blackout Tail Lamp |
| D | 90 | Ground |
| E | 21 | Service Tail Lamp |
| F | 23 | Blackout Stop Lamp |
Arrangement of the pins on the Turn Signal switch used on later M-Series vehicles:
| Connector Pin | Circuit Number | Circuit Usage |
| A | 460 | To front right signal/marker lights. |
| B | 461 | To front left signal/marker lights. |
| C | 22-461 | To rear left brake light. |
| D | 22 | From pin C on three-lever light switch. Indicates that brake lights are on. |
| E | 22-460 | To rear right brake light. |
| F | Power to flasher unit. To pin B on flasher cable. |
|
| G | 467 | From pin J on three-lever light switch. Hot when service stop or headlamps on. |
| H | Flasher pulse from flasher unit. From pin A on flasher cable. |