clb0099

Well … I am really trying to figure out why my w221 sporadically doesn’t start. I have scanned the car for codes and I get camshaft position sensors. Fuel pump, fuel filter. Spark plugs, coils, crankshaft position sensor , and other parts have been replaced including front/rear battery’s. The car cranks and wants to start but it seems like it’s getting no fuel. I have even replaced the fuel pump relay in the rear Sam. Sometimes the car starts and sometimes it’s doesn’t. Oddly enough the command screen doesn’t turn on unless I have someone press down on the rear sam relay plate which sits on top of the rear sam. The relay plates seems to need pressure on it for the fuses and relays to make contact something internal in the plate for it to communicate with rear Sam and the command works and sometimes starts

BOTUS

ummm.... the two parts of the Rear SAM (aka the SAM and the SRB) clip together - due to the hideously thrown together rats nest of badly routed looms and appallingly stupid location - trying to do this in situ means some people bend some of the pins on the SRB than electrically connect the two elements - with one pin bent its impossible to see if the two half are clipped together - some "professional" did this on mine and the car is mostly fine (indeed mine was like this for 2 years) but a bump or a wriggle can make the two disconnect certain circuits

I'd take out the rear battery and the stupid H frame and redo the routing of the looms so its possible to almost assemble the car correctly - and double check all the pin bush housing are correctly located with retention pins all intact - all the bits are available - the moron doing mine trying to do it broke one of mine and glued it back in !!!

clb0099

Botus,


I actually ordered an updated relay plate from 2010-2013 w221. It says it fits let’s see if this solves my issue