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Having what seems to be electrical problems after a heavy rain storm

Old Jul 7, 2022 | 09:16 PM
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09 c300
Having what seems to be electrical problems after a heavy rain storm

Hi everyone I have 09 c300 it’s a stick shift(don’t know if that would matter for my problem) we just had a heavy rain storm the other day I went to leave the house the day after and everything seem normal until I came to up to a stop I went to take off from the stop sign and every warning light came on center screen said esp inop, cruise control disabled, air bag lights I’ll lose my tachometer speedometer and coolant gauge sometimes it’ll cut power to the climate control then everything will go back to normal for a few minutes then do it all again just wanted to know if anyone has dealt with anything like this on these cars I work on Toyotas and Subarus so it’s way out of my field thanks in advance
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Old Jul 8, 2022 | 03:53 PM
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2008 C300 Sport
Check for water intrusion in the front SAM/ fuse box under the hood. There are several threads regarding this.
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Old Jul 23, 2022 | 01:23 AM
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2008 MB C350 4MATIC/2011 CL63 AMG/2014 C63 Coupe 507
Had this happen and replaced front sam i believe years ago. It started to do this again 2 years ago and i have left it till i gather some coin. I think its front or rear sam. Looked dirty a bit in rear right tailight section too. Goodluck
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Old Jul 23, 2022 | 06:43 AM
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2009 MB C300 Sport 4matic
As mentioned..Threads address this problem. Check the rubber seal around the driver's side wiper shaft as it comes through the plastic cowling. If torn water flows directly onto the front SAM area underneath. even more H20 if the drain area next to it is clogged. Google removal of front SAM to expose underside for drying and cleaning.
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Old Jul 23, 2022 | 09:34 PM
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W212 MY'14 M276-3.5NA @75kMi
Post locate rain entry point...

The fix is not going to be limited to replacing F-SAM
​​​​casualty. You need to find where the water entered and stop that from happening.

SAM's need to be coded so you can expect the round trip not to come cheap.

Check if the underside of your (L/R) front carpet is wet. This is evidence of internal penetration. F-SAM harness is built such that it can funnel water directly from A-pilar into enclosure tub.... check before it dries out.

I wish you the very best of luck to dry any MB electronics. It's built without conformal coating protection and with extra narrow gaps between circuit traces and GND/Vcc... oxydes develops in a rush.

The one thing that can increase slim chances of success is to DISCONNECT batteries (power down ASAP to discourage electrolysis).
🤞

Last edited by CaliBenzDriver; Jul 23, 2022 at 10:05 PM.
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