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Lightswitch

This component is part of Lights.

Definition

  • This articles covers the Column Switch (sometimes called Multi-Function Switch), the Headlight Switch, and the Fan Switch

Switches

In another section

Column Switch

There are two versions of the Column Switch. The switch for the 230 SL and the early 250 SL has a short, straight chromed stalk. These are used for the earlier steering columns without the safety crash buffer. The steering wheel is directly mounted to the hub.

The column switch for the later 250 SL’s and 280 SL’s has a longer, angled chrome lever. This style is for the later steering column designed to collapse upon impact and absorb some of the energy.

Late style Column Switch for later 250 SL and 280SL

Mercedes part numbers and list prices for new parts: Indicator switch 230 SL & 250 SL to VIN 002979: Part # 001 545 5524 list incl. tax € 487.90

Indicator switch 280 SL & 250 SL from VIN 002980: Part #002 545 2924 list incl. tax € 546.70 (Source: Mercedes-Benz Prices, as of January 2009)

Common defects

The column switch was not expected to be in use for over 40 years. As a result, the following are typical age and wear-related problems:

1. Blinker switch no longer stays in position

2. Turn signal cancellation is defective... excellent instructions on the forum here, still to be added to this document: http://www.sl113.org/forums/index.php?topic=3821

3. Wiper control defective.

4. Flash to pass feature defective

5. Windscreen washer defective.

6. Cracks in the plastic control unit

Koellner SL-Service can supply new stalks but also offers a replacement service at lower cost when your stalk is broken. See: http://www.pagode.info/50.htm Some failures can be repaired temporarily, but because of the delicate nature of the stalk and the column switch, they are unlikely to last.

Remove, Replace Switch, Re-Install. Read the entire article before starting.

For a W113 car with the steering wheel on the left side of the car. Disconnect car battery.

1. Remove the lower dash cover to the left of the steering wheel. It is held on by three screws visible form below.

2. After the pad has been removed, remove the two bolts which hold the plate in place. The plate holds the plug for the turn switch. Unplug the switch.

3. Carefully remove the rubber boot at the stalk base. If the boot crumbles, it can be replaced. About $35 from US parts dealers.

4. With the boot removed, the turn signal switch is visible. Remove the two philips head screws which hold the switch in place. Care that the screws do not fall into the steering column.

5. Loosen the two screws holding the black and brown wire ends for the horn contact.

6. The switch is now ready to be removed. The tricky part is to carefully feed the male part of the plug up through the steering column. The pins either need to face towards the inside or outside of the column. When you have the pins lined up correctly, the plug end will slide up through the steering column.

7. To install a new switch, reverse the process.

The whole job can be done in less than 30 minutes. Before putting in the replacement switch check for calcified grease in the switch mechanism. Age can gum up the switch. The springs might need replacement and check the tension.

On a 230SL, remove the steering wheel and the horn contact ring on the column by turning the holding bracket till it comes off. Remove the 2 wires that are connected to this ring. These two wires are part of the turn signal switch harness and must be removed before the Switch Harness can be taken out.

Note: the later Column Switch has two plug assemblies on the black plate. One for the turn switch the other for the center cluster instrument. You can see from underneath which plug goes into the steering column and which one disappears behind the dash. A problem is that the 230 SL turn signal switch has a larger bakelite plug (Kostal 8612) at the end of its harness. This plug does not fit through the steering column, too tight.

To fit the 230SL plug down the steering column, unscrew the 3 screws holding the plug together. Tape the two rows of electrical pins/contacts together. First tape each row separately then tape all the connectors together to make them as slim as possible.

When you first install the new switch with its harness, unscrew the new plug and tape the round electrical pins. To help guide the plug down the column, thread a copper wire down the column then tape the end of this wire to the wrapped end with the connector pins.

Pull the copper wire carefully through the steering column to help get the connector down the column. Moving the wire carefully back and forth will help guide it down. Then you can put the bakelite plug back on.

General comment: The difficult part is feeding the cable harness down the steering column. Easier when the plastic insulator is removed form the connector. Carefully note the position of each wire by drawing a diagram of each wire’s position. Be careful not to fracture or disconnect the wires from their female connector barrels. Also, check to see if there is enough detent on the control arm to hold it in position when turning.

Flash to Pass

Pulling the column switch toward the driver on European SL's switches the headlights on momentarily. If the headlights are already on, the headlight will alternate from dim to bright when the column switch pulled up. This is the Flash-to-Pass feature. Depending on which European country, the High-beams or the regular headlights are switched on. High-beams in Germany for instance, and regular headlights in Italy. On US cars this feature was disabled due to safety regulations. The wire that connects the fuse and provide power to the switch was disconnected and taped up.

To restore this function (make sure this is safe and legal in your area) find the taped up wire which might have been folded back and taped up. May have to start at the switch and work back to the fuse box tracing the wire while on your back and contorted upside down.

Remove the fuse box in the engine compartment. A taped white and purple/violet wire taped is the hot lead to the flasher on the lights. It was attached to Fuse 10. Find the proper lug on the back of the fuse panel on the side where the lights are connected. There should be a white/black lead on that lug.

Alternative possibility: the wires between the wiring block receptacles and the fuse panel may be missing. Look at the wiring diagram for Box 29. This is the Combination (Column) Switch.

In the center of the box is Switch B, the headlight flasher switch. The wiring diagram shows a wire connecting the right side of Switch B to Fuse 1 (the always live fuse). This is Pin 5 of the terminal block. The left side of Switch B shows a wire connected to Fuse 10 which provides power to the headlamps. This is Pin 8 of the terminal block.

On a Flash disabled car, the 10 pin terminal block which connects to the Combination Switch on a 1970 280SL may be missing the wires at Pin 5 and Pin 8.

Must add a female connector (metal receptacle) to the terminal block at Pin 5 and Pin 8. The wire from Pin 5 must terminate at Fuse 1. The wire from Pin 8 should terminate on Fuse 10 and the job is finished. These connectors can be ordered from parts suppliers.

This may be incorrect. Also see thread on forum at: http://www.sl113.org/forums/index.php?topic=554.0

Turn Signal does not Hold

LHD car: the right hand turn signal does not hold (or catch.) The Fix: pull the rubber cover off the steering column at the stalk end. Remove the two phillips screws,to loosen the stalk.

When the stalk is moved to the top position, the springs and a small rod with wheels will move. The wheels hold the stalk in the top position till the turn is completed. The curve that needs filing down is where the wheels stop.

The spring loaded rod must catch in the notch to keep the turn signal lever up or down until the steering wheel is returned to center and the mechanism forces the rod out of the notch.

Use a tiny rat tail file and CAREFULLY file the notch a little at a time until the rod will just hold the lever up until you turn the wheel back to center. If the notch is filed too deeply the lever will not cancel when the wheel is straightened.

Headlight Switch

230SL Headlight Switch Functions

280SL(early) Headlight Switch Functions

Note: On late USA-delivered 280SL cars the fog light function is disabled.

REPAIR

Fix for a Headlight Switch that sticks on a 230SL. All the lights work but the switch sticks -- particularly after using the fog light mode (switch pulled out).

Problem: The switch has several thin copper contacts inside which have "spread out" with the copper either catching the moving part of the switch when it is moved, or parts have "fused" together. If the parts are "fused" together will not work properly when the switch is turned on.

A fused or “spread” switch needs to be replaced – available from part suppliers. Installing a new switch can be a challenge. Must remove the tachometer (Rev Counter), method is explained elsewhere in this Tech Manual. See step by step below.

Transfer the wires from the old switch to the new switch ONE AT A TIME to make sure that the order is correct and the new switch functions the same as the old. Space is very small, tight fit for a large hand.

Steps to Replace the Headlight Switch:

1. Disconnect battery.

2. Removing the TACH is recommended. It makes this job much easier. Removing the steering wheel is also recommended, but not required.

3. Remove switch knob. Pull hard and straight out on the black plastic switch knob until it comes off.

4. Unscrew the chrome trim ring and remove the ring and the black switch plate.

5. Push the switch into dash cavity and pull it out into the footwell.

6. Remove one wire connection at a time and reconnect to new switch. This ensures all wires are reconnected correctly.

7. Once all wires are reconnected, carefully reinstall back into the dash by reversing the above steps.

Note: On some USA-delivered cars, the wiring may vary from this diagram, that is, the left and right parking light wires or the left and right fog light wires may not be connected.

Fan Switch

There is a bulb in the defrost fan switch and a hole in the knob to let the light through. Even with a new bulb and cleaned up the light can hardly be seen. Can be dimly seen from the passenger seat.

Suggest turning the fan switch on from time to time. This will keep the switch from getting "frozen" in position and will keep the fan from seizing.
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