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ML-350: do you have trailer symbol w/o trailer attached?
Hi, all, I am troubleshooting a blind-spot-sensor issue. Not surprising, of course: by now we have had 6 Mercedes cars, three of them with that system faulted. Ouch. $$$$$.
My question is to the owners of ML/GLE cars with factory towing setup.
When you go in reverse, does your display show the trailer symbol in lower right, even without the trailer connected? Or, only if the trailer is connected?
Thanks in advance, Robert.
Hi, Mike, thanks for reply.
Mine is a 2013, just standard rear-view camera.
My blind spot system is out and it almost seems like it is erroneously sensing a trailer, which normally does disable the feature.
I just don't remember if the trailer icon shows up only then.
This would help me chase the trouble - whether it's in hitch wiring or in the usual water ingress into the radar units. I want to keep checking these myself, before I go to the dealer. Last time I had the radar unit replaced, it worked out to be a close to $2k exercise.
Robert
Last edited by rdwalker; Jul 25, 2023 at 09:29 PM.
The radar sensors themselves don't throw the vehicle into "tow" mode which disables blind spot assist amongst other things. Only the trailer connection would be able to do that. But if the vehicle was sensing a trailer, why would it disable the trailer view function?
You mentioned that you had replaced your radar sensors before? Did you ever check the harness itself? I had an issue with my radar sensors being disabled, and there was corrosion on my radar sensors in the rear bumper. But it wasn't the actual sensor that had failed, it was the harness that had corrosion damage. Do you have an MB scanner? That would help a lot with your diagnosis.
Thanks! The sensor I replaced a couple of years ago was on a W212 E350 wagon. Expensive fun.
My wife's current W213 E300 sedan has the occasional fault after heavy rain, but I cannot convincingly duplicate it for the dealer.
On the ML-350 I am writing about, I did not replace the units - yet. But, I had my mechanic replace the connectors going to the sensors. I got the eBay kit, which has pigtailed connectors and splices. You cut off the OEM ones and get clean harness ends. Mine did not look good once we dropped the bumper - ugly corrosion both on harness and sensor side.
I was hoping for the best, though, got a clean run for a couple of months, but last week it went into full failure mode. I should add that this was after driving in heavy rain... as much as I hate to admit it, it sounds like one or both sensors are shot. My local dealer charges just under $900 for the part alone, ugh.
I do like M-B cars (we currently have 4 between the two of us), but corrosion issues in electrical and structural components remind me of my Brit cars in the past. Just last month I had to take apart the side mirror in my E63 wagon: the turn signal connector was so rotted out that there were no conductors left at all. In the aforementioned E350 wagon, the rear subframe just collapsed.
And yes, I do have the M-B scanner, but right now it shows no faults, despite the obvious problem. But it shows "trailer hitch detect", which sent me into the rabbit hole of chasing trailer connector issues. Which was probably a normal status.
Robert.
Last edited by rdwalker; Jul 25, 2023 at 09:59 PM.
What is the current behavior of the blind spot assist system? When the sensor fails you will get the "Blind spot assist unavailable" warning on the dash. With your MB scanner are you able to read module data from both left and right side sensors?
Aha! Mike was right. My scanner shows no communications with the right-side sensor.
Now I need to place bets: trip to the dealer for approximately $2k (that's what I spent for my previous wagon), or taking a chance on the $400 unit from PartsGeek, plus indy shop replacement, plus dealer programming. Ouch. Again.
I'll give you even better odds: Swap your left and right sensor, can you now read the right side sensor? If you can, it's a sensor failure. If you can't it's harness failure which is significantly cheaper. Also, there is no dealer programming for these, they are plug and play with the correct part numbers.
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