Hello, first post. Really hoping to find some help here. Ok so I had just bought this 06 S55 that has had a bunch of new parts on it and that came with it. But in short is this. It had been sitting in a garage for the last 4 yrs. He has changed out the ABC pump and it needed finished. Did all of that (but the drivers side has dropped so I think it must have a leak) Anyhow put it all back together and it fired right up!! So happy and relieved. Everything worked on it just perfectly. Best day!! I bring it home and life happens, so I didn’t get to drive it again for maybe 2 weeks. I get in it and it felt moist, because it had been raining that entire time. I start it up and the screen is doing some funky glitching. I am thinking “Oh great!! Of course here it goes”. I throw on the heater and within a few minutes it’s working as it should. Phew!! So i figure I better let it run longer and get it good and dry in there. So I do and everything is great. I’m getting familiarized with everything. About 10-15 min into it, it suddenly just shuts off!! I’m like that is weird. Went to try to restart it…and it has never started since!! So I have been trying to find everything i can about it and really there is not allot for this. I have read about fuse 52 & oh!! One important factor is that when it was talking about fuses it says be sure to close it tight. So I go to check fuses under the hood in each corner (which btw is THE STUPIDIST PLACE TO PUT ALL YOUR MAJOR ELECTRONICS!!) I noticed that one side of the slide lock was latched correct but the other side was just dummy locked and not making the correct seal. I check the other side and it is exactly the same!! I couldn’t believe it. I checked everything I thought so closely before starting it. But for whatever reason never checked any fuses to find this issue. I tend to think it is the cause of all of this. But I don’t know. I turn on the ignition and alll the lights come up as normal. Or what I know as normal. I had only started it a few times. But seems like it’s all normal. It doesn’t make a noise, doesn’t seem to do anything at all when I try to start it. Lights all stay the same. Oh but my coolant fan is running on high for some reason. Plz help me get this figured out. I want to drive this so badly and it has been sitting for months now. I felt so defeated. But spring is here now and I gotta get this back on the road. It’s a beautiful car, everything is immaculate. So upsetting. I bought a diag that says for Mercedes but when I hooked it up I found that it is for all the years and models directly AFTER mine!! Ugh. Thank you in advance for any help. T

 

Sounds like you got some water in the ECU possibly. First I would pop the hood, and pull out the big black plastic "screen" below the passenger side windshield. Get down inside of that box with a flashlight and make sure its clean and clear of any debris. That is where your water runoff is located, and also the reason that if you are getting water inside the car, especially the passenger side footwell, thats the reason. I know because i had the same issue. Once you clear it, take some water and pour it down there to make sure it drains properly and not still clogged or backing up. Now ironically, thats also right where your fuse box is for the ECU and TCU. I would start pulling the Large silver ECU out of the box, and check the connections and see if you have any water in there. If you do, don't panic. Throw it in a bag of rice and dry it out. Theres a chance you may have gotten lucky and the water has just caused a short issue. Get some contact cleaner, a clean rag, and a test light and start going through all of the fuses and relays. Check for corrosion, split wires anywhere, and make sure all the fuses with a TEST LIGHT are coming back hot. Once the ecu is property dried out, re-connect it and see what happens. I would start there first.

- Joe

 

OP the test light Joe refers to will use an incandescent light bulb. I swap the puny light bulb they come with for the bulb used in the dome light of a 123 Chassis Mercedes. Long and skinny. Will draw enough amperage to make clear there is 12 volts on each side of the fuse. ‘Voltage testers, logic testers’ consistently use LEDs or tiny bulbs or even a high impedance volt meter that will lie to you saying there is power there that won’t operate an electrical circuit.

 

You said the blower motor ran properly until the car shut down? Makes me wonder if the water got in a different way. It's happened to me, but I got lucky. Coco Mats soaked up most of the moisture and a couple days with a box fan dried things out with no ill effects. You might try checking the fuse box located just above the floor under the passenger side rear seat. Not entirely sure what's controlled there but it's a thought.

 

I want to thank all 3 of you for taking the time to share this info with me. I have been wondering which side is the one I should be looking at. Now I finally know. It’s the passenger side fuse box under the hood. I will keep you posted with what I find. I have been putting in crazy amount of hours with my work, but DAMNIT!! I WANT TO DRIVE THIS CAR!! I have wanted one for so long
Thanks again!!

 

Ok so I did everything outlined. Took out the ecu and didn’t see any signs of water intrusion. I opened up the ecu and didn’t see any physical signs of any blown components. I couldn’t see the bottom side bcuz I don’t know what all is involved in getting it opened to where I can see it. Looks like it is glued to the bottom half. I can see where moisture could get into the backside. Which is ridiculously designed. It’s like they took precautions but then leave two open spots on each end where water could easily get in. Especially facing upward. So it’s possible that there could be some signs on the backside. But what I don’t want to do is cause any further problems by damaging something trying to check it out. So testing the fuses I found that a large orange 40amp fuse on the passenger side the second one from the front ddxsde isn’t getting any power. On the drivers side the small red fuse in front of the relays has no power and the row next to that one the large fuse in front of those relays also has no power. Hopefully this info leads to something. Again thanks to whoever takes the time to give me their advice that helps me get this back on the road. Much appreciated.

 

Hate to say it but it sounds like Star Diagnostics time.

 

What is this?

 

It's an advanced scanner used by Mercedes Benz shops and dealers to identify various issues that can also be purchased online. Me? I'd find a shop that has one and see what they come up with.

 

Ok so I guess there is a misunderstanding about the fan. What I had meant to describe is that since this has happened, when I turn the key on…for some strange reason the radiator fan starts running full blast without any way to get it to shut off. It wasn’t doing this until the incident happened. It seems like an indication to something. Or at least that is what I was hoping for. Such as, oh when the radiator fan begins running top speed as soon as you turn the ignition on it comes on. Yet no crank, no click, no light twitch or any indication that I am turning the switch to try to start it. So upsetting.

 

Well I appreciate the suggestion. But even tho I bought this car knowing that it is expensive to work on. Yet I have always done my own repairs. So I have most tools (except diagnosed equipment). My hopes are to be able to do as much as possible myself. I did purchase a great diag tool from “Auto-Aid” that hooks up to the OBDII connection and my laptop with internet hooked up. It is extremely thorough. Only problem is that it doesn’t have a specific option for my car. It has all the S55 models 07 and up. Is there any models that you think might be compatible for diag? It said all Mercedes but in the fine print it said to verify. Sure enough I missed it by a year!! Anyhow this tool had it worked would have been AMAZING!! Anyhow. I would rather buy a starlink so as to be able to work on my car plus be able to help others in a bind like myself as well as be able to buy other Mercedes with some issues and be able to fix them hopefully. Rather than take it to a shop and spend all this money until another thing happens again and again. Instead I prefer to use what would have been spent in a shop to buy my own tools. Unless it is like over 2grand. That would be out of my range of budget. Unless I could maybe use it to program keys and it is very user friendly and makes sense. Anyhow if anyone has an idea of what model would be similar in diag requirements that may be on this diag tool I have. Thank you

 

[QUOTE=TheRealTroy;9171395]Well I appreciate the suggestion. But even tho I bought this car knowing that it is expensive to work on. Yet I have always done my own repairs. So I have most tools (except diagnosed equipment). My hopes are to be able to do as much as possible myself. I did purchase a great diag tool from “Auto-Aid” that hooks up to the OBDII connection and my laptop with internet hooked up. It is extremely thorough. Only problem is that it doesn’t have a specific option for my car. It has all the S55 models 07 and up. Is there any models that you think might be compatible for diag? It said all Mercedes but in the fine print it said to verify. Sure enough I missed it by a year!! Anyhow this tool had it worked would have been AMAZING!! Anyhow. I would rather buy a starlink so as to be able to work on my car plus be able to help others in a bind like myself as well as be able to buy other Mercedes with some issues and be able to fix them hopefully. Rather than take it to a shop and spend all this money until another thing happens again and again. Instead I prefer to use what would have been spent in a shop to buy my own tools. Unless it is like over 2grand. That would be out of my range of budget. Unless I could maybe use it to program keys and it is very user friendly and makes sense. Anyhow if anyone has an idea of what model would be similar in diag requirements that may be on this diag tool I have. Thank you[/QUOTE

Good luck mate!

 

OP get with BenzNinja. Buy the membership. Buy the equipment. Learn to use it and ask for help from Peter. He is great!

A radiator fan at full speed says it is not getting a signal. They default to full speed to prevent overheating.

 

I knew that had to have significant value. Now it’s just a question of why it is not getting a signal. Any ideas what would be giving a signal to the fan? Also I took out the ecu and which I am assuming is the silver box. How do I access the bottom of it. From what it seems it looks like maybe I just need to get a razor and slice thru the black rubbery substance. But not positive and don’t want to cause any damage at all and make my situation worse.

 

Sounds like fried ECU. Gonna need more than a couple nice wrenches to fix this.

Running with the heater on isn’t how to dry electronics.

Get it open and look for crusty green stuff on the board.