Newbie to this side

[innov8]

I'm an active member of the Porsche side of Pelican's forums but have never posted to this community. Hoping someone can help. While driving my wife's 2005 E500 4matic wagon (w211), the front defroster was blowing very hot and at an unusually high speed. When I turned it off, the HVAC controls and the dash all died... the tach and speedo froze on position and are not in op. The car starts, all lights and radio work... even the glove box lights work so they are definitely all on different circuits. I immediately checked the fuses in the left dash panel, then the rear block on the back and then the fuses in the front left engine compartment. I can not find any broken fuses.

Initial research has mixed messages about the SAM module and whether that is a DYI part replacement or not. Have read that they need to be programmed to the car, etc. I don't have advanced testing (only basic but since the systems are totally dead, how could the diagnostic tool test them anyway?

I've located diagrams for the fuse blocks in the only mention I find of the "Front Pre-Fuse Power Distribution (F32)" with "F75 40A fuse for N10/11 Passenger SAM-P" (is this the dash board) and "F76 40A fuse for N22 Air conditioning control module" (I assume this to be the HVAC controls). I am now onto the pre-fuse distribution block and those 40a fuses.

Does anyone know anything about changing them as a DYI?

Pelican does sell the SAM part# Part #: 211-545-91-01-MBZ
Any help would be great. Thank you,

[innov8]

OK... to recap what I was able to check and eliminate as a DYI:
—removed negative cables from front (small) and rear (large) batteries... both tested normal
—checked the pre-fuses in the distribution box on the floor of the passenger side... all
—my cheap OBDII reader reports no codes
—Autoparts store (slighty) more advanced code reader reported PO600 error... which is a communication link problem...
—revisited all the fuses (engine compartment, left, dashboard left, trunk left) and relays and everything appeared normal...

Rather than lay out $499 for a new SAM module which is what I suspected, I spent $125 at a local independent shop with the STAR software to read the MB modules and confirm.

Best $125 I ever spent. There is a second fuse box in the engine bay (right side though I didn't see it myself) that the mechanic replaced... cleared all the codes and everything is now working again. There is still a short fault in a fan motor controller that is probably the original cause of the problem.

Lesson learned? Don't replace parts unless you are certain that they are the source of your problem. The money you spend on the diagnosis will pay for itself in your time and cost of unnecessary replacement part purchases.

Good luck everyone. I hope my experience helps someone facing similar issues.

[Dmitry at Pelican Parts]

Glad that you were able to address this issue and save a good amount of $$ - if you're ever looking for other DIYs for your wife's 05' E500, be sure to check out the link below. Cool to see the Porsche community utilizing our other forum too!

Mercedes-Benz E-Class W211 (2003-2009) Technical Articles - Pelican Parts


-Dmitry