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Wiring Diagram
This component is part of Electrical Systems.
Definition
The appropriate wiring diagram for the 230SL, 250SL or 280SL is included in the Owner Manual. During the years the electrical system of the car went through a number of changes. Especially the US mandated anti-pollution measures are badly documented.
The Pagoda SL Group has published color coded diagrams for its members, courtesy of and copyright of Joachim Ahlert. These are accessible for Full Members here: Color Wiring Diagrams.
These comprise three diagrams:
- Wiring Diagram for the early 230SL, May 1963
- Wiring Diagram for the 230 SL, January 1966
- Wiring Diagram for the 280 SL, August 1970
As a courtesy we provide a high quality grayscale version of the 280 SL wiring diagram, and a copy of a 280SL US version wiring diagram, showing additional features such as the transistorised ignition and emissions control relays.
- 280SL Wiring Diagram Note: 584K, use your Save As function.
- 280SL (US Version) Wiring Diagram
Note: The description "Idle Increase Solenoid" for item 51 on "280SL (US Version) Wiring Diagram" is incorrect. The idle increase soleniod is uni-directional (extended when energized, spring return), whereas the solenoid on the schematic is bi-directional. What is shown appears to be the transmission solenoid which is three position with two coils, extended, mid positon, and retracted. The wiring indicates extended positon when the "venturi control switch" is closed, and retracted position when the "kick down switch" is closed, which is the function of the transmission solenoid. The "Idle Solenoid" does not appear on this schematic, nor do the forward and reverse auto-transmission pressure switches.
An exceedingly useful document is enclosed as a download in the Connectors section. It lists all connectors, pinouts, and colours of the main wiring circuit. If one of your connectors has broken and you need to hook it up again, this document is essential.
Colors of the Wires
The following official German Mercedes-Benz abbreviations of the colors for the wires are used:
| Abbrev. | Color | German |
| bl | blue | blau |
| br | brown | braun |
| ge | yellow | gelb |
| gn | green | grun |
| gr | grey | grau |
| rs | pink | rosa |
| rt | red | rot |
| sw | black | schwarz |
| vi | violet | violett |
| we | white | weiß |
Example: 1,5 sw/gn/rs means: 1,5 mm2 cable diameter, black cable with green and pink marking lines.
Legend
| Nr | Description |
| 1 | Lighting unit, right |
| 2 | Lighting unit, left |
| 2.a | High beam |
| 2.b | Low beam |
| 2.c | Direction signal light |
| 2.d | Parking light |
| 2.e | Fog light |
| 2.f | Clearance light |
| 3 | Glove compartment and reading light |
| 4 | Switch for glove compartment light |
| 5 | Heater blower switch |
| 6 | Electric clock |
| 7 | Entrance light and switch |
| 8 | Speedometer light |
| 9 | Revolution counter light |
| 10 | Instrument cluster |
| 10.a | Blinker control light, left |
| 10.b | Blinker control light, right |
| 10.c | Fuel reserve warning |
| 10.d | Fuel level indicator |
| 10.e | Instrument cluster light |
| 10.f | Regulating resistor for illumination |
| 10.g | Charging control light |
| 10.h | High beam control light |
| 11 | Loud dual tone horns |
| 12 | Heater blower motor |
| 13 | Illumination, heating control |
| 14 | Door contact switch, right |
| 15 | Door contact switch, left |
| 16 | Windshield wiper? motor |
| 17 | Relay for wiper motor |
| 18 | Direction signal transmitter |
| 19 | Relay for Electromagnetic Starting Valve (on early 230 SL) |
| 19 | Luggage compartment lamp with switch (on a 280SL) |
| 20 | Time switch (on 230 SL) |
| 20 | Relay for automatic starting aid (on 280 SL) |
| 21 | Relay for automatic starting aid (on 230 SL) |
| 21 | Relay for Mixture Control (on 280 SL) |
| 22 | Windshield washer pump |
| 23 | Brake light switch |
| 24 | Back-up light switch |
| 25 | Cigarette lighter |
| 26 | Signal ring |
| 27 | Socket |
| 28 | Fuses |
| 29 | Steering column switch |
| 29.a | Blinker switch |
| 29.b | Headlight flash switch |
| 29.c | Windshield washer switch |
| 29.d | Windshield wiper switch |
| 29.e | Switch for wiper speed |
| 29.f | Plug connection for steering column switch |
| 30 | Series resistance |
| 31 | Electromagnetic starter valve |
| 32 | Thermo time switch |
| 33 | Magnet for mixture control |
| 34 | Brake fluid control switch |
| 35 | Foot dimmer switch |
| 36 | Rotary light switch |
| 37 | Ignition starter switch |
| 38 | Spark plugs |
| 39 | Ignition coil |
| 40 | Battery |
| 41 | Starter |
| 42 | Voltage regulator |
| 43 | Generator |
| 44 | Fuel feed pump |
| 45 | Transmitter for fuel gauge |
| 46 | Plug connection tail light leads |
| 47 | Distributor |
| 48 | Tail light, right |
| 48.f | Identification light, right |
| 49 | Tail light, left |
| 49.a | Direction signal light |
| 49.b | Tail light |
| 49.c | Back-up light |
| 49.d | Clearance light |
| 49.e | Brake light |
| 49.f | Identification light, left |
| 50 | Becker radio |
| 51 | Luggage compartment lamp with switch (on a late 230SL) |
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