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Steering Column Switch (or Multifunction Switch)

This is a component of the Electrical Systems.

Definition

The combination switch on the steering column serves to operate the two-stage windshield wiper, the electric windshield washer, the headlight flasher and the blinker lights (turn signals). The Mercedes-Benz handbook refers to it as the Multifunction Switch also.

Components

The complete unit consists of multiple parts: a combination electric switch (a) on one end, connected via a chromed lever (b) to a mechanical/electrical swivel unit (c) that is attached to the steering column jacket, and on the other end a shielded wire bundle (d) with a 12-prong male connector (e).

Note that the lever stalk in the 280SL switch has a kink whereas the one in the 230SL unit is straight and shorter.

The 230SL switch unit is different from the 280SL switch unit and the two are NOT interchangeable!

Mercedes part numbers: 230 SL & 250 SL to VIN 002979: Part # 001 545 5524 (Fits both LHD and RHD) 280 SL & 250 SL from VIN 002980: Part #002 545 2924 (LHD) or 002 545 5424 (RHD)

Function

Push operation button and release (1): Windshield wiper engaged.

Tumbler switch in button: push down at left (I) - normal wiper speed push down at right (II) - fast wiper speed Pushing the button again will disengage the windshield wiper, while the tumbler switch will return automatically to position (1).

Swivel lever counterclockwise (2): blinker lights left.

Swivel lever clockwise (3): blinker lights right.

Turning steering wheel in straight ahead driving position will return lever automatically to its starting position; also possible manually.

Pulling lever (4): headlight flasher; the high beam is engaged as long as lever is pulled. Note: this function is usually disengaged on US model cars!

Pushing lever forward (5): electric windshield washer pump is engaged. Washer pump will run as long as lever is pushed forward.

Maintenance

Removing the column switch

Disconnect the battery!

Although not necessary it helps to remove the steering wheel.

And one more tip:

The cable can be pulled through the steering column jacket without removing the connector. Once the connector has entered the jacket use your left index finger to guide/push it through the narrow passage way while pulling/twisting gently on the other end.

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. Turn signal not self-canceling

This happens frequently after removal of the steering column and re-installation. There is a plate or boss on the steering shaft that moves pin on the swivel switch back to the neutral position.

If the shaft was not properly indexed during re-installation and rotated then it will not cancel the turn signal. However, if the shaft is centered correctly and still does not cancel the turn signal switch then the pin on the switch is worn off and too short. One way of fixing this problem is described here: http://www.sl113.org/forums/index.php?topic=11100.msg74187#msg74187

2. Blinker switch no longer stays in position ... excellent instructions on the forum here, still to be added to this document: http://www.sl113.org/forums/index.php?topic=3821

For German speaking members a detailed repair article can be downloaded here: http://www.pagodentreff.de/diskussionsforum/attachments/4044d1161610159-download-anleitungen-wissensdatenbank-blinkerschalter.pdf

3. Turn signal lights not flashing although emergency flasher works.

4. Wiper control defective.

5. Windshield washer defective

6. Flash to pass (high beam flasher) feature defective.

The first approach here is to bench test the individual switches using an Ohm meter.

Testing Individual Switches within the Column Switch

Switch FunctionConnect Pin Numberto Pin NumberResistance Change (Ohm)
Right turn signal39∞ ⇨ 0
Left turn signal310∞ ⇨ 0
Wiper push button switch67∞ ⇨ 0
" (Toggle position: I)24∞ ⇨ 0
Speed toggle switch I ⇨ II24∞ (no change)
Speed toggle switch II ⇨ I24∞ ⇨ 0⇨ ∞
Washer: push lever switch16∞ ⇨ 0
High beam: pull lever switch58∞ ⇨ 0

The male connector on the column switch connects to a female connector mounted under the dash board.

Note: Because the high beam flasher was illegal in the USA the female connector on US version 280SL cars has no wire terminals in position 5 and 8. These connections need to be reestablished for the flasher to work again.


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