jodiesel

Hello fellow Mercedes owners.

The wife had a cooler in the back that the water drain plug was not in. Went to the park and....well you know. The drain was directly on top of the rear SAM unit.

2011 R350 Gas
I do have the service/parts manuals.

After her picnic, she had a hard time opening the door with the wireless remote. Had to have it right next to the sensor on the driver's door handle. She could not get the tailgate open. On her short drive home, systems started failing. First the turn signals and wipers. Then the Supplemental Restraint System, then the stability control system, then the battery. So, I started checking fuses and after removing the spare tire to get better access to the rear fuse and relay panel discovered a couple gallons of water under the spare. I removed the rear fuse and relay panel as well as the rear SAM and blew them dry. Reinstalled, but still no work. I'm pretty sure the rear SAM is toast and am working on getting that replaced. However, my real question here is in regard to the rear fuse and relay panel.

There are two relay units, light grey, part # A 002 542 81 19 in the center of the panel in positions S & T. Both of these relays were so hot that I could not touch them. And this was with the engine and ignition off for about an hour. I assume those relays were that hot due to the rear SAM malfunctioning or possibly water in the rear fuse panel. They would still get hot even after I blew the panel and sam dry. What is strange to me though, is that when I plug that Mercedes number into an online parts ordering website, it comes back with those parts are not for my make/model. When I google search them, it comes back with diesel glow plug relay timer (I have the gas engine). Any idea if these are the correct relays for my application? The parts manual I have seems to state they are correct.

Also, I'm thinking I should try replacing the rear SAM and rear fuse panel right off. Closest dealer is an hour and a half tow truck ride. I'm trying to buy a rear SAM that have it pre-coded and mailed to me. Any suggestions would be appreciated.

Thanks,

Jodiesel

kombifan

Buy a new rear sam. It only needs to be coded if you have led taillights or tow package and some other things.

Fuse block could be useful. Check all connections for corrosion and clean it off. Check your tailight seals while you are at it. They should be on the body not the tailight

ygmn

Bummer.

I would pull relays out and ensure they are not filled with water.

Agent-A01

Be sure to spray with contact cleaner

jodiesel

UPDATE. I installed a reman rear SAM and a new rear fuse and relay box. I was surprised that the fuse and relay box came with most of the fuses and relays. Probably all the base ones and not the options. After installing, now all the errors are gone from the screen and everything works except the gas gauge and the passenger electric seat controls. I'm going to take to a place Monday that can hopefully program the rear SAM.

kombifan

Those remaining issues are likely from the front Sam. Did you check that one for water intrusion?

jodiesel

Last update. The programming/encoding of the rear sam did the trick. All items functioning again. Dream Cars of Victorville, CA got her done. For the future, I bought the wife a nice secondary containment mat for the cargo area that will hold a lot of fluid.....

chassis

Great news.

Another suggestion is to throw away the cooler with a drain plug and replace it with a cooler with no drain plug.