Couple of days ago I go out to start my SRT. 40k plus miles and never a single glitch with her till now. She starts but flashes a few warnings on the dash along with being stuck in park. Without paying any attention to the dash warnings I turn off the car hoping she'll reset and go to restart her and nothing. I get all lights, radio, wipers, door locks. Everything electrical is working but not even a click from the starter. NOTHING! I can do the manual release for the shifter and push the car but still no start in neutral. Always stuck in park. I ask the wifey to check my brake lights and nothing. So I figure it's the infamous brake light switch. I happen to live down the road from Ecklers which stocks Mercedes parts and found the switch for $12.99, a bargain! Put her in and still nothing. Battery is fairly new, pull terminals and thoroughly clean them, along with checking all grounds, which were pristine. No change in attitude. So I dig out the RCM which has been soldered once before. Decide to re-solder, reinstall and STILL NOTHING. Pull the board out once more, grab my handy magnifier glass and inspect the relays.
EUREKA! The relay closest to the edge of the board shows that the small flat round contact bead that's welded to the copper plate has disintegrated. All other relays are in perfect condition. There was actually nothing left that could be sanded down for better contact, so relay needs replacing. Since I have 2 XFs I decide to order (new) one of the AIRTEX / WELLS Part # 1R2032 RCMs from RockAuto. 2 day shipping and got her in today and "BodaBing" she's starting up and running normally again, like nothing ever happened! I'll be sending my infected board the D.J. to get repaired as a backup!

 

Glad to hear you got her going. I bought a spare RCM a few years back to keep with me. Any pics?

James

 

Nice! And I second the motion for pics.

 

That is the air pump relay and that would not stop the car from starting, you have another problem.

 

Well, we'll see after I get the board rehabbed. The new RCM fixed whatever is wrong with the old one!

 

Still trying to get the macro to shoot clearly. Here's a pic from another thread that shows the exact same fried contact as mine has....one on the left is the damaged one!

 

Glad to hear your back up and running!

 

Thanks everyone. I truly understand anyone's frustration when the car just quits. Especially when you start looking for a place to start diagnosing our finicky electronics and find no blown breakers and no codes thrown!

 

Roll eyes as much as you like but new parts have the habit of fixing old problems, but the air pump loss would not stop the starter from working. Faulty solder joints in the RCM will stop the starter from operating. A new RCM should not have those bad joints therefore it should start. I was pointing out the fact that it was not the burnt contacts and that the problem lay elsewhere.
I hope the problem is solved and the problem does not arise again.

 

Isn't the second relay from the left the fuel pump? Does the powertrain control module feed from there?

 

He's right.