I have 2005 Crossfire Roadster with very low mileage. It's been running beautiful all summer, just tried to start it today and it won't turn over. All dashboard light indicator, head lights are working but nothing when I turn the key. It does sound like a fan is turning on but nothing. Any thoughts, please.

 

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-CFK

 

Three things come to mind, has the alarm siren been disconnected, how old is the battery and have you changed the RCM? A bad RCM will cause this.

 

Thanks for the quick response, Alarm has not been discontinued, Battery is new and charged and no i have not replaced the RCM

 

THE ALARMS HAVE BATTERIES THAT LEAK WITH AGE AND SHORT OUT DRAINING THE STARTER BATTERY AS THEY GET OLD. Sorry about the caps, hit the wrong key. The RCM can have bad welds or burnt relays.

 

Indications from all is that it's the RCM. Thanks for your help!

 

Here is what to do:

Get in car, turn key to START, if starter won't engage, release key to "ON" . Sit there, wait 45 seconds.
Do you hear the engine fan running at high speed?

If yes:
Order a new RCM. PUt it in and the car will start. Take old RCM, ship to DJ for rebuild so you have a spare.

If no (fan does not warp up to high speed):
This can be bad starter/clutch interlock, bad pulse module, bad battery (terminal voltages under about 10.8 will result in no crank), SKREEM issue, etc. Much more 'detective work' is required to isolate this.

 

rbasm, Shoot me an email for the info on getting the RCM refurbished.
tighed1@hotmail.com

 

I took my 2005 Roadster (18k miles) for an afternoon drive yesterday. About 35 miles out the engine died (no noise or warning). I coasted to the side of the road and tried to start it. All dash lights on but it did not click or turnover. Two nice people separately stopped and tried to jump it to no avail. Everything electrical seemed to be working. I had it towed home ($250) since I’ve learned not to mention the word “dealership.” Today I fully charged the battery but it still would not turnover. Is this the RCM issue that I have read about here?

 

Use my procedure in post #7 and you will know.

 

Hi mwe74, It's the same issue for my 2005 Roadster. Car was driving great and one morning nothing. I was lucky it happen in my garage, towing to my local for repair, hopefully. Good luck with yours.

 

Did you read post #7 and #10?

 

Thanks to you experts and your advice. I tried to start it a couple of times on Sunday, but with no change. It did not click or turn over and all the dashboard lights were on.
Just now I tried again to see if the fan came on like Pizzaguy suggested. Low and behold it started. What next? I obviously don’t trust it now. Thanks. 🤔

 

Still say sticking, pitted relays in the RCM. A replacement is under $200.00, and you can swap them yourself in 5 minutes. They are plug and play.

 

Thanks. So I need to order a new RCM? Can you recommend a good source and the identity for this part?

 

Amazon for $170, Mercedes part.

 

Go to ANY of these: FCP Euro, PartsGeek, Autohaus Arizona, German Auto Supply and search for "2003 Mercedes SLK320 Relay Control Module". Prices this morning are running $155 to $193 for the same part.

 

If you’re half way decent with a solder gun, you can repair the RCM yourself takes 10 mins. There’s posts on here how to repair. Check relays aren’t sticking or burnt while it’s out of its shell

 

Thanks to all. I have ordered a new RCM from Amazon and mailed the RCM from my XF to tighe1. The harnesses were tougher to remove than I expected. I hope I didn’t damage them. All to do now is wait. Again, big thanks to y’all.

 

Do an Internet search and there are videos of how to change it.