TSBs and How-To Articles This is for information on Technical Service Bulletins and for posting How-To Articles.

How to Repair Relay Control Module (RCM) - (Mystery no Start)

Thread Tools
 
Old Apr 5, 2017 | 11:34 AM
  #1061 (permalink)  
Chrisjlyon's Avatar
Joined: Apr 2017
Posts: 73
Likes: 0
From: Nc
Default Re: How to Repair Relay Control Module (RCM) - (Mystery no Start)

Thanks. My car definitely has some differences. I will double check later and post the difference. Maybe someone can help figure out why it's different.
 

Last edited by Chrisjlyon; Apr 5, 2017 at 12:58 PM.
Reply
Old Apr 5, 2017 | 02:36 PM
  #1062 (permalink)  
Chrisjlyon's Avatar
Joined: Apr 2017
Posts: 73
Likes: 0
From: Nc
Default Re: How to Repair Relay Control Module (RCM) - (Mystery no Start)



My fuse box underhood
 
Reply
Old Apr 5, 2017 | 02:44 PM
  #1063 (permalink)  
Chrisjlyon's Avatar
Joined: Apr 2017
Posts: 73
Likes: 0
From: Nc
Default Re: How to Repair Relay Control Module (RCM) - (Mystery no Start)

So No 4 & 6 were different sizes than what you showed me. Rather than 30 & 15 they were 7.5 & 5 respectfully. Also where you show 16 as a spare, mine definitely has contacts in the socket with a 30 fuse installed.

Any ideas. Legit reasons it's different or should I just make it match what you sent and try it?

Thanks again.
 
Reply
Old Apr 5, 2017 | 03:41 PM
  #1064 (permalink)  
ala_xfire's Avatar
Senior Member
Joined: Dec 2010
Posts: 12,780
Likes: 184
From: Lineville, AL
Default Re: How to Repair Relay Control Module (RCM) - (Mystery no Start)

What I sent is just cut and paste from the 2004 service manual and 2004 owners manual.
I cannot say what is actually correct !
 
Reply
Old Apr 5, 2017 | 07:06 PM
  #1065 (permalink)  
Chrisjlyon's Avatar
Joined: Apr 2017
Posts: 73
Likes: 0
From: Nc
Default Re: How to Repair Relay Control Module (RCM) - (Mystery no Start)

So I resoldered the RCM. No change. I jacked the car and tapped the starter and it fired up. So much for the last guy replacing it. I let it run for a bit then shut it off. Put it back together and now it won't start again. I did change out the fuses to match the manual's diagram. I guess I'll replace the starter before anything else. Also while it was running the radio wouldn't turn on and the spoiler wouldn't go down. Not sure where to start on those. Thanks again guys
 
Reply
Old Apr 5, 2017 | 07:16 PM
  #1066 (permalink)  
BenzFire's Avatar
Joined: Jun 2010
Posts: 33
Likes: 0
Default Re: How to Repair Relay Control Module (RCM) - (Mystery no Start)

Originally Posted by Chrisjlyon
Glad to see this wonderful thread. Thanks for all this hard work! I just bought a 2004 that has had horrible starting issues. The last owner had replaced starter, alternator, battery, ignition and computer. It worked for him for a few months and now it won't start again. I just got it in my garage yesterday and have the battery on a charger since it was dead. My question is if this RCM solder joint issue causes the car to not even crank or try to turn over?
That is correct, solder joint issue could cause it to not even crank or try.
Can you hear the fuel pump prime sound / buzz when you turn the key once? (Acc position)
pay attention to the rear & right area of the trunk for the noise.
No fuel pump noise + no crank or try to crank = RCM not detected by computer = bad joints or bad rcm

Also, when the battery is extremely low the RCM won't respond correctly
once fully charged, reconnect it and have the driver door closed .. lock and unlock with the remote OR lock and unlock with the key in the drivers side door handle sometimes when the battery has been removed for more than 24 hours after installing the new battery or a fully charged battery the alarm system acts up and wont allow the car to start ( no crank no try) until security module receives a proper recognition command from the key or control
 
Reply
Old Apr 5, 2017 | 07:22 PM
  #1067 (permalink)  
BenzFire's Avatar
Joined: Jun 2010
Posts: 33
Likes: 0
Default Re: How to Repair Relay Control Module (RCM) - (Mystery no Start)

Originally Posted by Chrisjlyon
So I resoldered the RCM. No change. I jacked the car and tapped the starter and it fired up. So much for the last guy replacing it. I let it run for a bit then shut it off. Put it back together and now it won't start again. I did change out the fuses to match the manual's diagram. I guess I'll replace the starter before anything else. Also while it was running the radio wouldn't turn on and the spoiler wouldn't go down. Not sure where to start on those. Thanks again guys
Glad you mentioned that, when my RCM had bad solder joints the spoiler would go up on it's own
and I would not be able to lower it with the button. You'd be amazed at how many things are linked
to the RCM I wouldn't put all my money on the starter just yet. keep testing!
 
Reply
Old Apr 5, 2017 | 07:31 PM
  #1068 (permalink)  
Chrisjlyon's Avatar
Joined: Apr 2017
Posts: 73
Likes: 0
From: Nc
Default Re: How to Repair Relay Control Module (RCM) - (Mystery no Start)

Just also discovered that fuse 7 under the hood is blowing when I turn the ignition. Just went through three of them. Anyone have a schematic? I think I'll also be sending my RCM off to get fixed.
 

Last edited by Chrisjlyon; Apr 5, 2017 at 07:50 PM.
Reply
Old Apr 6, 2017 | 06:51 AM
  #1069 (permalink)  
ala_xfire's Avatar
Senior Member
Joined: Dec 2010
Posts: 12,780
Likes: 184
From: Lineville, AL
Default Re: How to Repair Relay Control Module (RCM) - (Mystery no Start)

Not good - BCM :

 
Reply
Old Apr 6, 2017 | 09:11 AM
  #1070 (permalink)  
Chrisjlyon's Avatar
Joined: Apr 2017
Posts: 73
Likes: 0
From: Nc
Default Re: How to Repair Relay Control Module (RCM) - (Mystery no Start)

Thanks fire. I noticed though that the schematic you just showed me states a different fuse size in no. 6 than the fuse box diagram you shared earlier. Looks like according to this schematic my fuses were right originally. I am going to reset then to the way they were before proceeding.
 
Reply
Old Apr 6, 2017 | 11:44 AM
  #1071 (permalink)  
BenzFire's Avatar
Joined: Jun 2010
Posts: 33
Likes: 0
Default Re: How to Repair Relay Control Module (RCM) - (Mystery no Start)

Your original fuses were correct, ( see pic )
I can't stress enough on getting the RCM repaired before trying anything else.


 
Reply
Old Apr 6, 2017 | 01:50 PM
  #1072 (permalink)  
Chrisjlyon's Avatar
Joined: Apr 2017
Posts: 73
Likes: 0
From: Nc
Default Re: How to Repair Relay Control Module (RCM) - (Mystery no Start)

I shipped it off an hour ago. Tighed should get it next week and hopefully I'll get some good news.
 
Reply
Old Apr 6, 2017 | 07:00 PM
  #1073 (permalink)  
Chrisjlyon's Avatar
Joined: Apr 2017
Posts: 73
Likes: 0
From: Nc
Default Re: How to Repair Relay Control Module (RCM) - (Mystery no Start)

So on the topic of no starting and bad connections. I pulled my starter off while I wait for my RCM to come back. Look at what I found on the starter. I believe it's a ground strap connecting the starter solenoid to the starter motor case.


 
Reply
Old Apr 7, 2017 | 07:58 AM
  #1074 (permalink)  
ala_xfire's Avatar
Senior Member
Joined: Dec 2010
Posts: 12,780
Likes: 184
From: Lineville, AL
Default Re: How to Repair Relay Control Module (RCM) - (Mystery no Start)

I do believe you are correct, and that does not look too good.
Can you repair it ?
 
Reply
Old Apr 7, 2017 | 08:50 AM
  #1075 (permalink)  
Chrisjlyon's Avatar
Joined: Apr 2017
Posts: 73
Likes: 0
From: Nc
Default Re: How to Repair Relay Control Module (RCM) - (Mystery no Start)

Not sure what kind of repair can be made. I am hoping to take it in and get it tested.
 
Reply
Old Apr 7, 2017 | 10:00 AM
  #1076 (permalink)  
ala_xfire's Avatar
Senior Member
Joined: Dec 2010
Posts: 12,780
Likes: 184
From: Lineville, AL
Default Re: How to Repair Relay Control Module (RCM) - (Mystery no Start)

Originally Posted by Chrisjlyon
Not sure what kind of repair can be made. I am hoping to take it in and get it tested.
Clean up the little bent out tab real good, solder a #6 or 8 wire to it and run to the ground lug with an eyelet. ( Alabama redneck shade tree fix )
 
Reply
Old Apr 7, 2017 | 11:03 AM
  #1077 (permalink)  
Chrisjlyon's Avatar
Joined: Apr 2017
Posts: 73
Likes: 0
From: Nc
Default Re: How to Repair Relay Control Module (RCM) - (Mystery no Start)

It passed twice at the parts store. Unfortunately no load against it but better than I expected. Guess I'm down to the RCM. Ready for it to be running
 
Reply
Old Apr 7, 2017 | 01:13 PM
  #1078 (permalink)  
GraphiteGhost's Avatar
Senior Member
Joined: Jul 2009
Posts: 6,323
Likes: 773
From: Central South Carolina
Default Re: How to Repair Relay Control Module (RCM) - (Mystery no Start)

Originally Posted by Chrisjlyon
Not sure what kind of repair can be made. I am hoping to take it in and get it tested.
Originally Posted by ala_xfire
Clean up the little bent out tab real good, solder a #6 or 8 wire to it and run to the ground lug with an eyelet. ( Alabama redneck shade tree fix )
Originally Posted by Chrisjlyon
It passed twice at the parts store. Unfortunately no load against it but better than I expected. Guess I'm down to the RCM. Ready for it to be running



George has a great answer, that lug looks sturdy enough to solder to. Use a HIGH wattage iron, DO NOT let it melt where the solder is at the plastic base (you can see a wire at the far left of the burned out strap, looks like it is soldered from internal wiring). You do not want a cold solder joint at the fix, nor do you want that (left side) internal wire to get loose if that solder holding it gets liquid, that will probably result in being stranded down the road. IF the fix is 100% reliable, your OK. If it isn't (or you are not comfortable with that large a solder repair job), then replace that starter. I do not know if there is a 'rebuild' kit available, that includes that strap. I am sure there are much lower prices for this starter, than at a Chrysler or MB dealership or parts jobber. Your choice! Good luck with your fix! BTW, I have never seen such a failure, I wonder what caused that kind of fault?


A footnote, looking more closely, you might be able to 'bridge' that gap if it is very well cleaned, and you have a small chunk of copper bar? If so, you can 'heatsink' off that tab that George mentioned which might help keep that left side solder point from 'melting' and pulling that wire out from within the starter. No matter what route you take, if it were mine, I would be 100% sure of the fix (OR) have a boxed starter in the rear if I thought it would fail again (with all the tools needed).


.
 
Reply
Old Apr 7, 2017 | 01:50 PM
  #1079 (permalink)  
onehundred80's Avatar
Senior Member
Joined: Apr 2006
Posts: 25,432
Likes: 647
From: Ontario
Default Re: How to Repair Relay Control Module (RCM) - (Mystery no Start)

Originally Posted by GraphiteGhost
George has a great answer, that lug looks sturdy enough to solder to. Use a HIGH wattage iron, DO NOT let it melt where the solder is at the plastic base (you can see a wire at the far left of the burned out strap, looks like it is soldered from internal wiring). You do not want a cold solder joint at the fix, nor do you want that (left side) internal wire to get loose if that solder holding it gets liquid, that will probably result in being stranded down the road. IF the fix is 100% reliable, your OK. If it isn't (or you are not comfortable with that large a solder repair job), then replace that starter. I do not know if there is a 'rebuild' kit available, that includes that strap. I am sure there are much lower prices for this starter, than at a Chrysler or MB dealership or parts jobber. Your choice! Good luck with your fix! BTW, I have never seen such a failure, I wonder what caused that kind of fault?


A footnote, looking more closely, you might be able to 'bridge' that gap if it is very well cleaned, and you have a small chunk of copper bar? If so, you can 'heatsink' off that tab that George mentioned which might help keep that left side solder point from 'melting' and pulling that wire out from within the starter. No matter what route you take, if it were mine, I would be 100% sure of the fix (OR) have a boxed starter in the rear if I thought it would fail again (with all the tools needed).
.
If you have a welder nearby who works on tools you might be able to get it micro or laser welded, these generate much less heat.
 
Reply
Old Apr 7, 2017 | 01:51 PM
  #1080 (permalink)  
BenzFire's Avatar
Joined: Jun 2010
Posts: 33
Likes: 0
Default Re: How to Repair Relay Control Module (RCM) - (Mystery no Start)

Dang! Isn't it supposed to look like the pics below?
I'm curious as to what brand that starter is.



 

Last edited by BenzFire; Apr 7, 2017 at 01:53 PM.
Reply



All times are GMT -4. The time now is 12:06 AM.