Bill1962

I'm going to recheck the fuses. I think one is missing?

I have a 2005 C320. There's a bit to this story... mystery. It RAINED for 2 days. We live at the ocean. I think there was enough oxidation (two other people I know had starter problems that next day) and the car did not start at all. No click.

After a few days of guys messing with the fuse box and diagnosing, it would click. That's it.

The indy Mercedes tech ran a diagnostic test and said it was the computer. And it was bad an needed to be replaced (plus keys, steering lock).

The car has 193k on it. I had it towed home and dropped off.

I spent a few days fiddling with it off and on. Using the hair dryer and checking fuses.

Today I pulled all of the connectors off the computer and sprayed them with carb cleaner as that's all i had. I opened the computer and wiped it down. Closed it up and put it back together.

IT NOW CRANKS!

But does not start.

I checked and there is fuel at the rail and it reprimes just fine.

I'd like to know what fuses exactly need to be in place to start and I'll reseat/replace those. Do you know which fuses they are?

What else? Thank you in advance.

Bill1962

I watched this video...


my starting sound is much slower, the cranking attempts.

DjaKRAbb

Hello, dont forget that all that cranking is going to drain your battery. Do you not trust the indy mercedes techs diagnosis? you have made some progress so well done.

some info on fuses if it helps https://fuse-box.info/mercedes-benz/...uses-and-relay

also out of curiosity, are the water drains under the wipers blocked or anything?

Bill1962

Thank you Dj. The water drains are probably blocked there are leaves in there now.

I'm starting the car with a big battery next to it to jump with extra power. I'm speed charging the main battery now, although it was at full charge starting.

The entire computer area seems as it got wet enough to cause oxidation. We live just north of Miami at the ocean, across the street and some days the salt is very strong in the air. It had something to do with the super big rain event we had.

It was at NO Start, No turnover. No Click.

I got it to Click and now turn over. Fuel goes and there is some fuel pressure... just no starting.

DjaKRAbb

Lets get those drains unblocked, stick something down the drain pipes and thats another thing accomplished, good job. All of this battery charging / jumping is making me nervous, its dangerous if you dont know what you doing, im scared to touch my own battery now.

Do you have spark? (i dont have a clue how to diagnose a 'no spark' correctly) you need fuel, compression, and a spark, seems like you have 2/3

would be helpful to know what error codes or diagnosis that lead the mechanic toward his opinion

*Your slower cranking is a bit worrying though. Something like this might need an auto electrician to diagnose it. a slow crank can also be a bad ground connection "Clean the terminals first then check the ground system. Sounds like a bad ground wire" is something ive read along with generic troubleshooting advice here https://www.mercedesmedic.com/mercedes-wont-start/

Bill1962

Thank you again DJ. The black battery cable is quite corroded. I'm going to clean the drains and see if I can track down DeOxit and clean the computer connections and clean up the battery connection... in the morning.

Will update.

DjaKRAbb

The more i learn about auto electrics the less i know. take this video for example of what diagnosing a problem involves:

The possible problems are endless and it takes a professional to diagnose. If diagnosedan told you that you need a new "computer" and "keys" i'd believe him.