Originally Posted by bieber

Yesterday I ordered some relays, intending to repair my RCM.

Today on the way home I went by a wreckers that has an SRT6 to get a spare RCM. The car's hood and the cover to the box the RCM is in were missing, the RCM had become full of nasty water and was junk. I am glad they let me go out to the car, supervised by a yard employee.

I asked the guy at the counter when I retured if he had a SLK320. He said yes, and asked if the employee that went to the SRT6 with me knew what I needed. I said yes and he went in the back to send him out to get it (without me).

The item he returned with was a different P/N (W210, E class?) but other than the single 20A fuse in my RCM being a 15 in this one, I could not tell any external difference. The pins etc... were identical. It was cheap enough that It was worth the gamble and I bought it.

The car threw another P0410 code on the way home!


I opened both RCM's up and my old one has pitted contacts on the air pump relay, the new one looks good. My old one has the "mystery no start" solder that does not look very solid, the junkyard item appears much stronger.

I really scrutinized them both inside & out trying to find anything different between them, but they really seem the same. I switched that one 15A fuse for the 20A to match the Crossfire RCM and installed the junkyard RCM. So far so good, everything seems to operate OK.

Has anybody else found/used a MB RCM with a W210 P/N? Am I flirting with electrical disaster?