b16

Hey All,
I have a 2009 C63 with close to 80,000 miles on it. A few times at night I've noticed when the switch is ON and foglights ON, the headlights will cut out for a few seconds; intermittently. It was a little scary at first.

I also notice sometimes in A mode they do not turn off, even when it is quite bright outside.

Has anyone had their light switch fail on them? Are these the symptoms you had? Is there any kind of TSB on this switch?

Thanks,
-mike

drawde

i've had this happen before. it doesn't happen often enough for me to worry about it as i always leave the fogs in auto 99% of the time. when i do turn on the fogs i just give the knob a little shake lol and that works for me almost always.

AMGer

I noticed the same problem for a while now. Leaving it on Auto solved the problem. This is a dangerous problem but I can't reproduce it when I want it to in order to get it fixed under warranty. However I searched for answers and found the light switch is most likely the problem. To fix it you will need to replace it which doesn't look too hard to do either. I suspect the contacts in the switch are probably too worn over time.

Paculdo

i have a similar problem - when i set it to A, its intermittent - on the brightest day the lights are ON. I checked the settings and my DRL is set to OFF. I don't want the car that i'm following that they think I'm flashing the lights or something so I set the lights to OFF ("0"). Now it's behaving like its in Auto. No lights when its bright/day light. then switches to ON when night!

I'm just waiting for the Service A to come and have this checked.

b16

Agreed, this is what I do as well. I have come to the same conclusion. I think I'm just going to replace the switch and see if it fixes the problem.

Let me know if you find anything. My symptoms are the same as yours when using auto.

b16

Installed the new switch today. Was the easiest thing I've ever done on this car. Will update in a month or so to see if the problem is gone for good.

AMGer

I look forward to see if it'll fix the problem for you. I've been leaving mine on Auto and haven't thought about it since. If it does fix it I may replace mine too.

BiturboSF

How much was the headlight switch & where did you purchase it from? I see this is a common issue, I have the same problem as well as my right "eyebrow" light blinks on and off by itself sometimes when the car is off.

b16

So far so good! Even the courtesy lights are working as I remember now. To recap the progression of symptoms.
1.) I noticed my courtesy lights would not always come on when unlocking the car at night. It was intermittent.
2.) The Auto mode of the lights would sometimes keep the headlights on during a bright sunny day.
3.) The headlights would sometimes turn off when the switch was in the "ON" position.

They happened squentially like this. #1 Started first, then about a month later #2 started happening, then about 4 months later #3 happened. After that I decided to try replacing the switch and so far all of my symptoms have gone away!

I bought the switch here:
http://www.mymercedesparts.com

Items Ordered:
Item: electrical, chassis electrical, switches, headlamp switch C-Class
Price: $123.26
Qty: 1

Total (before taxes or discounts): $123.26

-----------------------------
Items Total: $123.26
Shipping Method: UPS Ground
Shipping: $9.75
_________
Order Total: $133.01

Exacc

Just wanted to add an update...The headlamp switch referred to by b16 is part number 204545 04 04.

I have the same problem and went to MB of Santa Monica, and requested this part from the parts department. They gave me 204 905 33 04...which on the receipt said is an updated part from part number 204 545 04 04. Looks exactly thesame and I am not sure why they updated the part number, perhaps a new supplier or some kind of an update. Anyway, will install later in the day, crossing my fingers, hope that it works. It cost $199 plus tax.

abcut973

Probably the update is related to the facelift model

Exacc

Perhaps. I haven't seen a headlamp switch of an updated model. This one looks exactly like the old one, just with a different part number. On the W204 C-Class thread, where they had the DIY for this, someone commented about transferring the chrome surround to the new switch. When I replaced the switch earlier this morning, the new part came with the chrome surround also.

anyway, just to confirm, I am delighted that the new switch solved my problems and installed perfectly. I have a 2009 W204 C63.

BiturboSF

Thanks! Good info

jvanbrecht

I had this problem about 2 years ago. It was fixed under warranty, and was apparently a known issue.

m a x i m u s

interesting, I'm having the exact same problems. I thought it was the auto light sensor, but I guess it's the whole switch.