How to Repair Relay Control Module (RCM) - (Mystery no Start)
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Joined: Jun 2009
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From: Fort Worth, Texas
Re: How to Repair Relay Control Module (RCM) - (Mystery no Start)
Oh my, I think I'm going to sit here and be very quiet..... 
Joined: Sep 2013
Posts: 255
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From: Tennessee
Re: How to Repair Relay Control Module (RCM) - (Mystery no Start)
Great INFO and instructions, I did mine today, I had the symptoms but the solder looked great on mine,
I reheated and put a little extra just in case.
I hope my ghost is gone!
I reheated and put a little extra just in case.
I hope my ghost is gone!
Joined: Sep 2011
Posts: 21
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From: Oberlin, OH
Re: How to Repair Relay Control Module (RCM) - (Mystery no Start)
My thanks also. My wife told me the other day that her battery was dead. The battery is only about a year old. I put the charger on it and made sure it was fully charged. Turned the key and nothing. All the lights and etc. were bright so I knew it wasn't the battery. Did a search here and found this article. Pulled the module and couldn't tell for sure but it looked like I could faintly see a ring around one of the pins indicating that it was loose. Reflowed and added a bit of solder to each of those circled in yellow, re-installed and instant start. Fantastic. Entire job took maybe 30 minutes.
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Joined: Mar 2008
Posts: 14,606
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From: IN
Re: How to Repair Relay Control Module (RCM) - (Mystery no Start)
LMAO....pjm....I have my lighter out...lol. Problem with the solder job is many don't get out the old magnifying glass to see what the hell they are doing...lets just solder the joint and it will be fine. There isn't anything to say that brand new MB part you just paid for won't do the same thing later on... They didn't go out and make that board yesterday. It has been laying in a parts bin for years.... I will solder mine until it flames then I will buy one thank you. AS one who loves to find more HP all the time...the RCM isn't one of them...
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Joined: Sep 2011
Posts: 9,595
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From: Kellyville, Ok
Re: How to Repair Relay Control Module (RCM) - (Mystery no Start)
Didn't I read MB actually did a recall on these for their cars? I would think if you could get the newest version - date wise - you would be okay.
Joined: Nov 2013
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From: Nashville
Re: How to Repair Relay Control Module (RCM) - (Mystery no Start)
Thank you so much for the information. The "BLUR" has been a mystery for quite awhile. Today, I fixed it myself! There were no issues with disconnecting anything. Put it some gas in it,and washed it, as a gift. I'm totally jazzed. I can't wait to tell my mechanic.
Joined: Dec 2010
Posts: 137
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From: Florida, U.S.A.
Re: How to Repair Relay Control Module (RCM) - (Mystery no Start)
Hey everyone,
Just recently at the grocery store, went to my SRT6, turned her on, and while driving out of the parking lot the car just shut off! Weird I thought, all in dash lights were on and working. I tried to crank her on again and she would NOT crank over at all! So, I went to check under the hood, battery connections looked good etc.
After checking things out under the hood for a good 10 minutes, checking the battery connections, etc. I decided I would give it another attempt at trying to crank it over before calling Road Side Assistance. Put the key in, turned to crank the car on and she fired right back up perfectly! I left the parking lot and the car was running smooth! This problem Has NOT happened since..
I have to mention that my battery and negative terminal post has been replaced approximately 2 years ago. When this situation happened and I was able to drive perfectly fine after it cranked over I did go to where I purchased my battery to have them test it and it came back Perfect. So that wasn't the issue.
As a preventive maintenance, I've been reading between thinking that its the Crankshaft Position Sensor or the RCM and I do believe with what happened that day that this is the RCM and since the OP is willing to offer the L-RCM service (and add the Me So Horny Mod LOL) then I think this is great progress at hopefully seeing if it eliminates the problem from hopefully ever happening again and if anything I got myself the Oh So Horny Mod done!!! hehehehe
I just PMed tighed1 and I'm looking forward to us swapping RCM's soon
Just recently at the grocery store, went to my SRT6, turned her on, and while driving out of the parking lot the car just shut off! Weird I thought, all in dash lights were on and working. I tried to crank her on again and she would NOT crank over at all! So, I went to check under the hood, battery connections looked good etc.
After checking things out under the hood for a good 10 minutes, checking the battery connections, etc. I decided I would give it another attempt at trying to crank it over before calling Road Side Assistance. Put the key in, turned to crank the car on and she fired right back up perfectly! I left the parking lot and the car was running smooth! This problem Has NOT happened since..
I have to mention that my battery and negative terminal post has been replaced approximately 2 years ago. When this situation happened and I was able to drive perfectly fine after it cranked over I did go to where I purchased my battery to have them test it and it came back Perfect. So that wasn't the issue.
As a preventive maintenance, I've been reading between thinking that its the Crankshaft Position Sensor or the RCM and I do believe with what happened that day that this is the RCM and since the OP is willing to offer the L-RCM service (and add the Me So Horny Mod LOL) then I think this is great progress at hopefully seeing if it eliminates the problem from hopefully ever happening again and if anything I got myself the Oh So Horny Mod done!!! hehehehe
I just PMed tighed1 and I'm looking forward to us swapping RCM's soon
Last edited by ThatSweetSRT6; Dec 1, 2013 at 09:48 PM.
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Joined: Dec 2010
Posts: 12,780
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From: Lineville, AL
Re: How to Repair Relay Control Module (RCM) - (Mystery no Start)
So, you are back in business again on the RCM fixes ?
Good, I didn't want to take over that awesome responsibility anyhoo.
Good, I didn't want to take over that awesome responsibility anyhoo.
Joined: Dec 2013
Posts: 6
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From: PORTLAND
Re: How to Repair Relay Control Module (RCM) - (Mystery no Start)
Joined: Dec 2013
Posts: 6
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From: PORTLAND
Re: How to Repair Relay Control Module (RCM) - (Mystery no Start)
I was wondering if the joints might see too much heat or if it's just a common defect. So far three out of three have had bad joints.
Folks. Might want to take a look at your RCM's before you get stranded! Don't say you weren't warned!
One of these days after a drive I'll remove the protective cover and check the temperture of the area of failure to see if it is higher than the rest of the board.
Folks. Might want to take a look at your RCM's before you get stranded! Don't say you weren't warned!
One of these days after a drive I'll remove the protective cover and check the temperture of the area of failure to see if it is higher than the rest of the board.
how do i go about switching mines with the loaner?
Joined: Dec 2013
Posts: 2
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From: London, UK
Re: How to Repair Relay Control Module (RCM) - (Mystery no Start)
Yes if you looked closely at the joints you could see there was a problem. However this is not a $1k part. Here is a brand new OEM unit available on eBay for $148...
Mercedes-Benz ASR / ABS Relay Unit - Stribel - 2105400072 - NEW MB Module | eBay
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Senior Member
Joined: Aug 2008
Posts: 5,742
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From: Sierra Vista, Arizona
Re: How to Repair Relay Control Module (RCM) - (Mystery no Start)
Hey! Welcome to the forum!
Yep. Still repairing them.
Send me a PM and I'll tell ya the procedure to get it to me.