While driving back home under cold weather 2 days ago, I smell something burning coming from the long front vent hole (windshield defroster vent) under the windshield, and it blew warm/hot air with that smell into the interior even I had the AC turned on. Initially I thought the warm and burning smell may be coming from the engine and sneaking in the car through the vent. When arriving home, the next day when I started the car everything seems normal but after 4,5 minutes the instrument cluster and radio display suddenly went total black and the engine still ran. I knew there is something wrong, and I connected a Bluetooth SDB2 scanner to the scan port trying to read the code, however the scanner could not be detected, I don't know what's wrong. I still can start and run engine in Park (not driving in fear it might shutdown on the road). I still can use the keyfob to open/lock the car doors and the trunk but I can not open or close the 4 windows when pressing the buttons on the driver door. I remember there was 2 inches falling snow/rain in the previous day so I looked for water in the footwell and under the right rear seat (where the SAM is), but I found there is no water sneaking in both areas.
Since I still can crank and start the car normally, I hope there might be simple electrical issue (short/blown fuses, etc...) but I don't know where to start. I need help desperately because I don't want to see it progresses into some serious issues at a later time.
Thanks in advance!

 

Had the exact same thing happen.

A fuse blew in your passenger side door fuse box. In my case it was the radio alarm that has a built in battery.
The instrument cluster, I believe the transformer blew. There are plenty of services for their repair.

 

First - it might help if we knew the original market for your car, as there are numerous differences in construction and options throughout the world.

Open the right front door, and look closely at the end of the dash. The sorta-triangular piece is the cover for a fuse box. Carefully pry the cover off, trying to avoid breaking off any small catches. One of the fuses in that box powers the instrument cluster.

Do you have the fuse chart for your car? It originally was a small paper, wrapped around one of the tools in the center of the spare wheel.

 

My car is 2006 S430. Pressing any button on the radio, driver door, frontal panel won't work. I'll try locating the fuses but need to find out what particular fuse.

 

Today I opened the passenger side fuse box next to the glove compartment and looked at fuses 79, 84, 85 (5A each) for Instrument Cluster, they are all good. Then I opened the driver side front fuse box and also looked at fuses 20, 21, 22 for Instrument Cluster, they are also good. Cranked the car, let the engine ran, and the Radio and the Instrument cluster are still black, no display at all, and no button can be pressed to operate anything.
I'd like to get help to enable the ODB2 so I can hook the scanner to the port under the steering wheel to scan for error codes, or at least where else to look for the display issue. Another thing is my left rear window is down 1 inch when all the buttons to control the windows were dead, I tried manually push it up with no avail, is there another way to raise it up?

Thanks!

 

cant obd just be hooked up either way to scan

 

Hello,

After several tryouts to see how to get the display back, all attempts failed. The engine still runs but I can not see anything with no dashboard, no radio display. II finally get the display back a few days ago, kind of miraculous or luck, if you will, without spending a penny but an hour work. I started out by removing the right front floor carpet to expose the cables underneath it, disconnect the red cable and all electronic wires that firmly attached by the nuts, and since bad thing happened when water leaked into the floor area, I waited for a hot, dry day, and ran a small portable heater that blew hot air to that area for a 5 hours, the idea is to dry out any water residue.

The next day, I opened the hood and pulled the front passenger side SAM out, I saw no water in that area. I happened to have an identical SAM (same model #) that I know it works on the other exact same S430 Merc. I connected the new good SAM in the car, then I tried to start the car but it did not crank (dead silent). I took it out and put the original SAM back in, the car started. I tried again using the good SAM again, it failed, I put the original back in and it cranked. I thought may be I messed with the wiring (lots of wires) up so I tried the third time by swapping the good SAM (it failed again, no crank). I told myself "That is it", it does not like the new good SAM, so I put the old SAM back thinking I will have the car towed and will spend thousands to have it fixed. After hooking the old SAM back, I cranked the car, it started again, then BOOM, I saw both the display coming back like normal. Wow, I am shocked but very, very happy! However, to be on alert, I drove the car near and far a few times in the past few days to see how it run. Today is the 5th days I've been driving the car and everything seems normal. What can I say? Did the good SAM revive the sleeping/death mode? If I did not try swapping SAM 3 times may be it's still dead, or is it a miracle or luck? Don't know but I know one thing for sure - I saved at least 1K, 2K if I have it towed, be diagnosed, SAM replacement, and blah blah blah.

What I learnt from this is:
1/ The water damaged SAM or the footwell soaked with water might be cured with drying them well. (Drying, drying, drying is the key word)
2/ The front SAM might not work by swapping with the exact same model SAM (It might have coded by VIN #), this I don't know!
3/ I know the rear SAM (under passenger seat) can be replaced by the identical same model SAM, I did that a few years back.
4/ I will regularly check and clear water that is stuck in the area next to the SAM, below and in front the windshield, passenger side. This is what forces water flowing into the footwell, the SAM, that damages the wiring and causes the electrical shocked to the SAM and the whole electronic system.

Afterall, I lost the driving for a month while the car sitting dead along with the extreme cold weather that I could not work on it. This evening, I drove to Costco, bought a bottle of wine, some cheeses, and sausages. I need to reward my relentless hard work. I thought spending less than $50 vs $2K is an extremely good deal, can not do better than that!

Hope it will help someone with water damaged SAM.

Cheers.

 

My first guess is that the water under the carpet caused some corrosion, consequently a poor electrical connection. Eventually, the electrons found their way again through the poor connection, and power was restored on the red cable. I doubt if swapping the SAM had any effect on the condition. Again, just a guess.

Glad that you can enjoy the car again.