The combination switch Part number W168 545 01 107 D88 on all models, is possibly one of the most used components on the car . As it is name implies it combines and carries out a number of functions being controlled by the driver and when it goes defective cause all manner of problems.
Items controlled by this switch include:-
Indicators (Direction Of travel indicators)
Windscreen wipers, 3 variable speeds and off
Front Windscreen washer, (Electric)
Headlight main beam /dip switch control. Head light flasher.
Head light flasher The head lights of the car will light when the switch is held towards you, the driver with the ignition ON. No other lights show Front or rear.
The head lights will remain on for as long as the switch is held, switch returns to off position when switch lever is released.
This facility is generally used to indicate to other drivers that you are giving way, to allow them to exit access junctions etc, On motor ways generally used to indicate to drivers of long/large HGV vehicles that there vehicle is passed you and that you are prepared for them to pull back into the lane in front of you.
Although both of the above are used extensively by drivers I'm not aware that they are in the official highway code. So if you are using these methods to indicate to other road users or indeed acting on this form of signalling always treat them with caution and expect the unexpected! (always treat them with caution)
Drivers will I'm also have seen this facility being used when dangerous manoeuvres are undertaken by drivers, again this is not an official warning and may cause confusion so be aware.
Main beam /headlight switch.
With Main lighting switch turned to ON/headlights.
The main /dipped beam facility/switch is operated by pushing the combination switch arm/lever away from you which will allow main/full beam lights to be lit.
The blue full beam indicator symbol as seen in the photo, will display in the instrument cluster when main beam is selected
Pull/flick the switch towards you and the lights will revert to dipped beam, main beam indicator goes out, no symbol is displayed.
Indicators
The indicator warning signal in the instrument cluster will flash at approximately the same rate as the human heart 72 beats per minute, in fact its slightly more at between 75 & 80 flashes per minute. The flashing being accompanied by a clicking sound. as well as the intermittent lighting of 4 main bulbs front & rear plus 2 repeater lamps situated in the front wings
The indicator flashing in the photo indicates we are about the turn left.
Both green indicator arrows illuminate when the hazard warning switch is pressed. The indicators are self cancelling. Having turned left or right the movement of the steering wheel will cancel the signal being given as it is re-centralised.
However attention should always be paid when operating the indicators to ensure they do cancel. If changing lanes on motorways for instance, the degree of movement of the steering wheel is not always sufficient to cancel the indicators, it is therefore necessary to cancel them manually.
Blown bulbs
The Speed of the flashing will be affected when bulbs blow :- If a repeater lamp bulb situated in the wings blows the speed of the flashers remain the same.
However if a main lamp front or rear blows the flashers speed increase dramatically so there is no excuse for driving with indicators that are not working correctly and in all cases the bulbs for the indicators can be replaced in minutes, providing of course you carry spares , which if your going abroad you are obliged by law to do.
I carry a complete set in the cubby in the boot area and they take up very little space. Remember you do need amber coloured bulbs on the 2001 onwards 'A' Class as the lenses are white.
Front Windscreen wash facility
The electric pump situated in the lower side of the windscreen wash fluid reservoir is operated by pushing the combination switch lever arm in towards the steering column. The action of the windscreen wipers and washer fluid is automatic as the lever is pressed the washer will spray the screen, wipers will make two complete sweeps of the screen and the automatically stop. if further washes as required the procedure is repeated.
It is worth knowing that the front washers nozzles on the 'A' class are heated and so so the problem of blocked nozzles due to icing should be illuminated.
Front Windscreen Wipers.
The windscreen wipers are controlled by the combination switch by turning the lever arm away from you, the driver, (Anti-Clockwise) Four setting:-
position.
O = Off
1= 1 x Intermediate sweep approx every 5-7 seconds (17-20 sweeps per minute)
2 = Standard speed approx 45-50 sweeps per minute.
3 = Fast 75-80 sweeps per minute.(These figures are on a wet screen)
Problems associated with the combination switch
Dip switch fails to dip main beam.
Broken lever
Indicators fail to operate correctly.
Windscreen wipers cannot be controlled, in one instance could not be stopped without turning off the ignition.
Pulling fuse 9 or 11 may resolve the problem, but it will effect other services so check before moving the car further.
In all cases the cause is a broken switch mechanism , that jams the switch, to change the switch necessitates removing the steering wheel and clock-spring which is possible DIY providing all procedures are followed closely . Where there is doubt the replacement of this switch should be left to the professionals, You do not need diagnostic equipment to undertake this job nor does the garage, so you should not be charged for it.
The switch costs approx £90.00 March 2009. So it is not cheap. However it is possible to repair the switch and this has been under taken now by a number of owners. If done well the switch will give no further problems,
certainly no more than a new switch which only comes with a 12 month warrantee. You can however reduce the possibility of switch damage by using it with c are and with out force and by keeping the ball where it entered the column housing lubricated, I use a light silicone grease and so far I have not had problems.
Note screw Numbered 2 (short screw) must be replaced in its original location or the steering lock may be damaged.
Arjan, was able to replace his combination switch following the guidance on this page saving a considerable amount of money in labour costs, the switch cost him 104 €, Arjan informs me he lives in the Netherlands, Welcome Arjan And thanks for the above photos.
Possible repair method
I also received information from one owner stating that he had managed to repair his switch and that at the time of mailing me some weeks after the repair it was still holding up and working fine.
He discovered when he removed his defective switch that the plastic has broken away ( shown by the red arrows ) from around a securing pin allowing the switch components to move around and therefore not operate the various facilities controlled by this switch.
This damage would have also caused the common fault which results where the head lamp Main/dipped beam switch fails to operate correctly, this fault invariably leaves the headlights set at main beam making the car unusable at night.
To drive the car in this fault condition at night would be highly dangerous to other road users even if the indicators were still working.
He managed to repair his unit using the metal barrels cut from two electrical cable connectors which he placed into the remaining portion of the broken holes and then plastic welded them in place, this could be also attempted with a heat gun or glue gun, allowing adequate time for drying and curing before re-assembly.
If you have problems meeting the high cost of this component then you may wish to give it a go after all you have nothing to loose in attempting the repair.
Please note I have not had to attempt this repair myself as my switch is still working the amended digitally adjusted picture shows what I feel the repair will look like after completion, although it is advantages to build the shoulders up above the holes ,this may not be possible due to the re location of the switch. only by looking closely at the housing and switch would you know if this was possible.
There a number of instances where the arm has broken off I can't comment on how this happened .What I do know is that the arm can get very stiff which may contribute to the problem ,I therefore keep this point on my switch lubricated with silicone grease.
Removing/replacing Combination switch
For information in respect of accessing the combination for repair or replacement purposes please link to page mypage.70. and follow the procedures If you do not feel confident to undertake this task please refer to a garage for assistance.
The Procedure on page 70, only needs to be followed to the point where you can remove the switch.
If using a none Mercedes Garage I will pay you to obtain the combination switch switch first.
DO not expect a commercial garage to undertake repairs to the switch.
Always quote your Vin number when obtaining spare parts for your car.
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