Cruise control stopped working

[campaholix]

2016 Melbourne

1600 miles and no issues. Stopped for lunch and back on I75 suddenly all I get when I try to set the cruise is 2 beeps and 2 dashed lines on the panel.

Any clue why this might be happening?

[Grumpy]

Bad or stuck brake light switch can cause that.

[campaholix]

Originally Posted by Grumpy

Bad or stuck brake light switch can cause that.

Thanks...working again today so I suspect you’re correct. Off to the dealer I go

[Grumpy]

Originally Posted by Dnbgould

Thanks...working again today so I suspect you’re correct. Off to the dealer I go

I'd hit the switch with a little dry lube spray and see if it happens again before I'd paid a dealer unless it's still under warranty.

[campaholix]

Originally Posted by Grumpy

I'd hit the switch with a little dry lube spray and see if it happens again before I'd paid a dealer unless it's still under warranty.

Good suggestion...if I knew where it was or what it looked like, I’d try it. Mercedes book has nothing in it

[Grumpy]

Originally Posted by Dnbgould

Good suggestion...if I knew where it was or what it looked like, I’d try it. Mercedes book has nothing in it

Should be at or near the top of the brake pedal arm under the dash. Found this on-line:

Lying on the floor (you might want to cover the seat runners/rails - I tore my shirt - but just an old T-shirt - you might be wearing something better) looking up into the underdash area where the brake parts are located you will first see the brake pedal then connected several inches higher, the rod going to the master cylinder then just above that by a couple of inches the brake pedal pivot/mounting point - just above that is the end of the pedal lever - you will find the brake switch that touches the end of the pedal to activate the brake lights and deactivate the cruise control. It is a small white plastic square with a "plunger" coming out of it to touch the end of the brake lever. With the engine running, press the brake pedal down as far as it will go and grab the "plunger" and pull it toward the end of the brake. It will come out from the switch and make a sound like very fine comb teeth being brushed across a piece of hard plastic. That is self adjusting teeth in the plunger that obviously did not self adjust. I actually did this a couple of times because I kept going to the back to see if the brake lights had gone out - they had not so I thought the fix had not worked. Not the case ....the brakes just had to "recycle" or clear it's throat. The cruise was once again working and the brake lights were out except when they should be on."

[campaholix]

Originally Posted by Grumpy

Should be at or near the top of the brake pedal arm under the dash. Found this on-line:

Lying on the floor (you might want to cover the seat runners/rails - I tore my shirt - but just an old T-shirt - you might be wearing something better) looking up into the underdash area where the brake parts are located you will first see the brake pedal then connected several inches higher, the rod going to the master cylinder then just above that by a couple of inches the brake pedal pivot/mounting point - just above that is the end of the pedal lever - you will find the brake switch that touches the end of the pedal to activate the brake lights and deactivate the cruise control. It is a small white plastic square with a "plunger" coming out of it to touch the end of the brake lever. With the engine running, press the brake pedal down as far as it will go and grab the "plunger" and pull it toward the end of the brake. It will come out from the switch and make a sound like very fine comb teeth being brushed across a piece of hard plastic. That is self adjusting teeth in the plunger that obviously did not self adjust. I actually did this a couple of times because I kept going to the back to see if the brake lights had gone out - they had not so I thought the fix had not worked. Not the case ....the brakes just had to "recycle" or clear it's throat. The cruise was once again working and the brake lights were out except when they should be on."

Awesome, thanks. I’m still on the road and hadn’t been able to do a comprehensive search yet. Appreciate the info

[Swill4wd]

Most likely an ABS wheel speed sensor. There is now a recall on them, but with no parts available. Use a scanner to identify which one. easy to replace with aftermarket part until Mercedes gets their act together, save the old part for replacement when genuine parts available.

[campaholix]

Originally Posted by Swill4wd

Most likely an ABS wheel speed sensor. There is now a recall on them, but with no parts available. Use a scanner to identify which one. easy to replace with aftermarket part until Mercedes gets their act together, save the old part for replacement when genuine parts available.

Thanks