Originally Posted by
abcdcohen
Okay I checked the relays as you advised and only the one in the middle changed with the ignition on. Also, the fan below the relays is definitely working as I can hear it whirring around.
Do I need to replace the RCM?
Thanks
Anthony
We are not referring to the fan in the bottom of the box. While it is good it is runnning, the issue is this: When turning the key to "start", if the starter does not engage\ and you relax the key to "ON" and wait 45 seconds, if the engine cooling fan runs at high speed, your RCM is BAD. Period.
If you can leave the key ON for 45 seconds without the engine fan running fast, there is something else wrong. In every case, when the key is on, the engine control and traction control relays MUST pull in and stay in. The fuel pump relay will pull in and then, if the engien is not started, the pump relay will relax.
If the other two relays do not pull in and stay in, the most likely issue is the RCM. NO ONE should be without a spare.
Search online sources for "2003 Mercedes SLK320 relay control module". The SLK230 relay module works as well, same part, just different part number, that's the one I ordered, as it's $20uSA cheaper.
