On Thursday, I drove to Ohio, in bad weather, heavy rain, etc. I parked the car on an incline, put the parking brake on, it engaged and I got the red and yellow parking lights, and the parking brake not working message. The parking brake pulled away when I pulled away but the messages won't clear, I have the yellow parking light and I get the attention assist isn't working message. Parked for the night, it started fine the next day, drove it with the messages it was still raining I was hoping something was wet from a puddle and it would dry out. I checked out of my hotel this morning, and the battery is dead. I had to use the key to unlock the door. I'm waiting for Geico to send someone to jump me.

The battery and alternator are new. The install date was 4 months ago.

I have a long drive back to NYC. Is there a fuse I can pull to bypass the parking brake so I don't have to get the constant message and avoid a battery drain until I can get in to the shop next week? I'm scheduled to go to Marcy, NY, in a few days. I may need to rent a car, but for now, I just need to get back home. Please advise.

@BOTUS

 

not sure on the fuse likely where ever they hid it (will look later) - but the connector is actually easy to pop off

 

Fuses – Box in the Engine Bay – Front SAM Control Unit – N10/1 needs tools to open 4mm allen key or similar

F35 5 Amp Electric parking brake A13

 

Thank you!
I made it home. The car ran well.

It was a PIA to jump it. The booster box that the roadside tech brought was low on power. It wasn't strong enough to start the car. It put power to the battery and the parking brake message was on. He didn't want to use jumper cables. The tech had another tech bring out another jump box. It took a while for the battery to get enough power to start the car. Once it started everything was ok. No messages and everything worked. The tech had a Carly scanner and scanned the car and it went through the module diagnosis, including the parking brake and it passed. There were13 faults, all but one cleared itself.when he scanned it again. The one fault was for the driver side seatbelt tensioner not communicating with a module.

I drove over 4oo miles and it ran fine, no issues at all. I didn't and won't attempt to use the parking brake until I get it looked at. I don't know why this happened. Last weekend I flushed the radiator, changed the power steering and brake fluid as part of a service E. I noticed the connector for the master cylinder was a little loose, probably from me bumping into to it when I pulled out the little filter in the master cylinder. I don't know if it could have been something as simple as that or thoseif 2 systems are connected in anyway.

I have to check the carpets for and trunk for water intrusion, but I don't thing there was any. When I went into the spare tire well everything was dry and there weren't any musty smells.

My wife thinks my S-Class is jealous because it over heard me talking about buying a new car. Which I was, and am going to do, but it's NOT going to replace Onyx. (that's the cars name.)

Thank you for getting back to me @BOTUS . Which connector were you referring to?

It makes me sad to see this forum so quiet. This place used to be the place to be for Mercedes-Benz information.

 

the park brake sits mid way above the left rear drive shaft - with a pathetic rusty plate attempting to partly shield it from getting sprayed with road filth - its connector plug can be reached fairly easy - but remember with the air suspension death awaits the unfortunate playing at the roadside

I wonder if the issue is really the normal rear ABS sensor wires starting to breakdown - these throw the car in a right mess - sometimes failing to allow gear selection and making scary ABS ESP messages come up - due to the park brake auto-release capability, it has to have the ABS sensors behaving to know you are driving off

these are an easy home fix 20 mins per side - buy aftermarket the genuine ones are inferior quality (designed to fail)

 

I'm updating this thread with the cause of my issues. This past Thursday, we had rain again, and the car was having issues unrelated to the parking brake. The command wasn't operating properly, and the center console interior lights and controls weren't working. I realized that water had to be getting in. Sure enough, the front passenger carpet was wet. The air intake drain was clogged and filled with water. I unplugged it, checked the other drains, and all seems well now. The water is draining.

I check my drains regularly and changed the battery in January. I cleaned out the battery tray, which didn't have much debris. However, I didn't realize that the fresh air intake had its own drain and that's where my issue was.I've had this car for nearly 9 years and i'm still learning things about it.

Next up is a service E. I will do most of that maintenance myself. The trans and coolant service I will bring to the mechanic.