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2000 ML320; engine number 30 633407; last 6 VIN 172300
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363 Posts
Discussion Starter #1
I just replaced the brake light switch this summer to get rid of the ESP/BAS lights on the dash. That worked.
Now 6 months later, the brake lights are constantly on and the cruise doesnt work. There are no warning lights lit up on the dash though.
Does this point once again to the brake light switch? If so, why arent the lights on the dash lit up again?
 

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1990 190E 2.6,.... 1998 ML320, 2005 ML500SE
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3,103 Posts
I think the switch is either bad again or not installed correctly. Do the lights go off when you push the brake light switch button with your finger? If they do than the switch is not aligned correctly.
If I remember correctly, and I could be wrong, when you first install the switch it's button is too long and the first time you release the brake peddle it pushes the switch into proper calibrated position. If pushed too far the brake peddle will not push the switch enough distance to activate the switch.
Like I said I could be wrong but it's worth a try.
Mike
 

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2000 ML320; engine number 30 633407; last 6 VIN 172300
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363 Posts
Discussion Starter #3
I'm guessing it is bad again then. I'll try the finger push, but like I said, this was fine for at least 6 months, so it must have been installed correctly and calibrated properly. I wonder why these switches are such a common failure on a MB? I have never seen so many problems with a brake switch like I have on these cars. You would think for a $20 part, they could have room to improve the design and make it bullet proof and last as long as the car. I'd pay $50 for one if that were the case.
 

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1990 190E 2.6,.... 1998 ML320, 2005 ML500SE
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3,103 Posts
I'm guessing it is bad again then. I'll try the finger push, but like I said, this was fine for at least 6 months, so it must have been installed correctly and calibrated properly. I wonder why these switches are such a common failure on a MB? I have never seen so many problems with a brake switch like I have on these cars. You would think for a $20 part, they could have room to improve the design and make it bullet proof and last as long as the car. I'd pay $50 for one if that were the case.
It's more like a $0.50 part that Mercedes charges $20 for.
You probably installed it correctly but something could have bumped it out or alignment.
Mike
 

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2000 ML320; engine number 30 633407; last 6 VIN 172300
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363 Posts
Discussion Starter #5 (Edited)
When you say out of alignment, do you mean that the button is no longer making contact with the brake pedal? If that were the case, then wouldnt you expect that I *never* get the brake lights to light up, because the switch would always be open?
Edit: nevermind, I see these operate the reverse of the way I was thinking. I just installed the second one now, all is well.
 

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Registered
1990 190E 2.6,.... 1998 ML320, 2005 ML500SE
Joined
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3,103 Posts
When you say out of alignment, do you mean that the button is no longer making contact with the brake pedal? If that were the case, then wouldnt you expect that I *never* get the brake lights to light up, because the switch would always be open?
Edit: nevermind, I see these operate the reverse of the way I was thinking. I just installed the second one now, all is well.
Where did you get a replacement on Sunday?
Mike
 

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2000 ML320; engine number 30 633407; last 6 VIN 172300
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363 Posts
Discussion Starter #7
I ordered a new one from Autohaus last week, just had not installed it till now.
 
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