How to Repair Relay Control Module (RCM) - (Mystery no Start)
How to Repair Relay Control Module (RCM) - (Mystery no Start)
How to Relay Control Module (RCM) Repair - (Mystery no Start)
Click here to Go to post 120 for loaner RCM infoThanks LGV-XFIRE!
This post is in response to the MANY occurrences of the "Mystery No Start" issue. Symptoms being car will die and/or will not restart but may restart after waiting for a while. Also, when attempting to start the engine all electronics work but the engine will not crank.
Hundreds have been spent "repairing" this problem by buying a new Relay Control Module (RCM) and paying for diagnostics, removal and installation.
Well I'm here to help save you some time, $$$ and aggravation cuz YOU will do the repair yer self!
This repair will require that you are able to properly operate a soldering iron. Beyond that it’s pretty easy.
Let’s get started (get it?)!
First four steps might look familiar cuz they come right out of the “Me so Horny” mod.
1. Disconnect the battery.
2. Remove the cover that contains the RCM and pull the RCM out.
3. Disconnect all plugs from the RCM.
4. Remove the protective cover from the RCM. Might take a little prying with small screwdrivers.
5. Inspect the rear of the RCM. Pay particular attention to the area in the yellow outline box located in the lower right hand portion of the photo.
Here are two examples of what you might see.
This is NYPD-Crossfire’s BAD RCM.
And now the close up.
By just slightly touching the center set of connections I was actually able to make and break the electrical connection. No wonder his car wouldn’t start.
Here is my still “good” RCM from the coupe.
As you can see the connections here are also VERY poor. It’s still working but looking like it does it wouldn’t be long before I too would have encountered the Mystery No Start issue.
- REPAIR
Re-soldiered connections. Compare with the above photo. I think I'm safe now!
NOTE: Now would be a GREAT time to do the “Me so Horny” mod. Two deep cuts in the circuit board. Solder in two wires. That easy!
7. Put the protective cover back on the RCM.
8. Re-connected RCM.
9. Put the RCM back into the main box.
10. Install cover.
11. Connect battery.
Yer Done!
Last edited by tighed1; 08-07-2010 at 06:54 PM.
The following 2 users liked this post by tighed1:
Esinclair (02-07-2024),
MoparDriver (07-02-2023)
re: How to Repair Relay Control Module (RCM) - (Mystery no Start)
EVERYONE.
(UPDATED 1/26/2020 --- Disregard old information below in BLUE)
Don't spend $15-$20 mailing these. They fit in the padded flat rate envelopes and ship for about $8.
If you would like me to refurbish your RCM...
Send your RCM and $50 (cash, money order, check) to:
DJ TIGHE
3601 Pinnacle Ct
Sierra Vista, AZ 85650
I'll inspect, bench test, redo bad solder joints, perform the Me So Horny mod (horn works w/o key) and replace the Air Pump, Fuel, Engine and Traction Control relays.
I will then test your RCM in one of my cars before mailing it back to you via USPS Priority Mail (2-3 days).
In most cases, I get the RCM back in the mail the day I receive it so you're looking at about a week total. If you want the package insured please include an additional $5.
If you ship to me via a method that requires a signature it will extend your waiting time as I will have to go into town to sign for the package.
Leave all fuses and plastic cover on RCM.
Let me know what symptoms the car had.
Please email your address to me also.
tighed1@hotmail.com
DJ
Don't spend $15-$20 mailing these. They fit in the padded flat rate envelopes and ship for about $8.ress.[/FONT][/FONT]
Cost for rebuild is $50
If you are interested, here's the deal.
I will inspect, redo bad solder joints, perform the Me So Horny mod (horn works w/o key) and replace the Air Pump relay (and the Fuel Pump relay if needed). I will then test your RCM in one of my cars. Then I will mail back the RCM to you via USPS Priority Mail (2-3 day). In most cases I get the RCM back in the mail the day after I receive it so yer looking at about a week total. If you send it "Signature Required" return will be longer as I have to go into town to pick up the package. If you want the package insured please include an additional $5.
Please email your address to me also.
Leave all fuses and plastic cover on RCM.
* Please detail any issues you may be having (no start, cooling fan runs FAST, wing stays up, whatever).
Send your RCM and $50 to:
TIGHED1
3601 Pinnacle Ct
Sierra Vista, AZ 85650
(UPDATED 1/26/2020 --- Disregard old information below in BLUE)
Don't spend $15-$20 mailing these. They fit in the padded flat rate envelopes and ship for about $8.
If you would like me to refurbish your RCM...
Send your RCM and $50 (cash, money order, check) to:
DJ TIGHE
3601 Pinnacle Ct
Sierra Vista, AZ 85650
I'll inspect, bench test, redo bad solder joints, perform the Me So Horny mod (horn works w/o key) and replace the Air Pump, Fuel, Engine and Traction Control relays.
I will then test your RCM in one of my cars before mailing it back to you via USPS Priority Mail (2-3 days).
In most cases, I get the RCM back in the mail the day I receive it so you're looking at about a week total. If you want the package insured please include an additional $5.
If you ship to me via a method that requires a signature it will extend your waiting time as I will have to go into town to sign for the package.
Leave all fuses and plastic cover on RCM.
Let me know what symptoms the car had.
Please email your address to me also.
tighed1@hotmail.com
DJ
Don't spend $15-$20 mailing these. They fit in the padded flat rate envelopes and ship for about $8.ress.[/FONT][/FONT]
Cost for rebuild is $50
If you are interested, here's the deal.
I will inspect, redo bad solder joints, perform the Me So Horny mod (horn works w/o key) and replace the Air Pump relay (and the Fuel Pump relay if needed). I will then test your RCM in one of my cars. Then I will mail back the RCM to you via USPS Priority Mail (2-3 day). In most cases I get the RCM back in the mail the day after I receive it so yer looking at about a week total. If you send it "Signature Required" return will be longer as I have to go into town to pick up the package. If you want the package insured please include an additional $5.
Please email your address to me also.
Leave all fuses and plastic cover on RCM.
* Please detail any issues you may be having (no start, cooling fan runs FAST, wing stays up, whatever).
Send your RCM and $50 to:
TIGHED1
3601 Pinnacle Ct
Sierra Vista, AZ 85650
Last edited by tighed1; 09-01-2020 at 07:49 AM. Reason: update
The following 6 users liked this post by tighed1:
manlaw38 (09-07-2022),
MoparDriver (07-02-2023),
Thiebs (08-08-2021),
Trip (12-14-2020),
Whitcat9 (09-28-2022),
and 1 others liked this post.
Join Date: Jun 2009
Location: Fort Worth, Texas
Age: 64
Posts: 13,450
Received 880 Likes
on
686 Posts
re: How to Repair Relay Control Module (RCM) - (Mystery no Start)
Great job tighed1, I was wondering about the missing pics, so I looked at your gallery and there they were. When I got back they were in place.
Its amazing that there are so many badly soldered joints, are these done by machine or are they of such low quantity that they are done by hand? If they are done by hand then some of these solderers need to take soldering 101.
An added thought, better add that the soldering iron be about the right size, not to big and not too small. The solder should be resin cored solder not acid cored or plumbers solder as we would not want the acid to start ruining the job slowly.
Its amazing that there are so many badly soldered joints, are these done by machine or are they of such low quantity that they are done by hand? If they are done by hand then some of these solderers need to take soldering 101.
An added thought, better add that the soldering iron be about the right size, not to big and not too small. The solder should be resin cored solder not acid cored or plumbers solder as we would not want the acid to start ruining the job slowly.
Last edited by onehundred80; 10-26-2009 at 02:57 PM.
Join Date: Jun 2009
Location: Fort Worth, Texas
Age: 64
Posts: 13,450
Received 880 Likes
on
686 Posts
re: How to Repair Relay Control Module (RCM) - (Mystery no Start)
180:
I see this all the time in both Motorola and competitive equipment: they use the MINIMUM amount of solder to build the assembly.
They teach you to "not depend on solder for physical strength, always tie down and secure connections, boards, etc."
Which is stupid, cause....They also teach you to use the minimum amount of solder that will "do the job".
I spend a LOT of time resoldering broken connections in radios, sirens, lighting control boxes and other crap we put into police and fire vehicles. I must say, some stuff STILL comes back in a few years, no matter how much solder I use or how hard I try to "make it right".
But the fact remains, if you flow enough on there like in tight's "Me So Horny" modification pictures - you WILL have less trouble.
I see this all the time in both Motorola and competitive equipment: they use the MINIMUM amount of solder to build the assembly.
They teach you to "not depend on solder for physical strength, always tie down and secure connections, boards, etc."
Which is stupid, cause....They also teach you to use the minimum amount of solder that will "do the job".
I spend a LOT of time resoldering broken connections in radios, sirens, lighting control boxes and other crap we put into police and fire vehicles. I must say, some stuff STILL comes back in a few years, no matter how much solder I use or how hard I try to "make it right".
But the fact remains, if you flow enough on there like in tight's "Me So Horny" modification pictures - you WILL have less trouble.
re: How to Repair Relay Control Module (RCM) - (Mystery no Start)
I am assuming that any of the soldered joints may be suspect or is this spot the most likely point of failure?
If so this should be stated more positively in your post, otherwise people will just look at that one spot, add a bit of solder there and the car will still not start.
Great job, I am not being picky just trying to save later questions and assumptions that are not totally correct.
If so this should be stated more positively in your post, otherwise people will just look at that one spot, add a bit of solder there and the car will still not start.
Great job, I am not being picky just trying to save later questions and assumptions that are not totally correct.
re: How to Repair Relay Control Module (RCM) - (Mystery no Start)
Originally Posted by onehundred80
I am assuming that any of the soldered joints may be suspect or is this spot the most likely point of failure?
Originally Posted by onehundred80
If so this should be stated more positively in your post, otherwise people will just look at that one spot, add a bit of solder there and the car will still not start.
Great job, I am not being picky just trying to save later questions and assumptions that are not totally correct.
Great job, I am not being picky just trying to save later questions and assumptions that are not totally correct.
When I received NYPD-Crossfire's known bad RCM I tested the circuit paths through each of the five relays. It wasn't till the last relay (of course) that I encountered a problem (open). I then closely inspected all of the connections with a jewelers monocle and that is when I found the bad joints.
Out of the three RCM's that I have checked all had poor joints at the stated location and no where else. This is not to say other joints might not be bad and since you have the RCM out you might as well inspect all of it.
But as far as the Mystery no Start issue goes I am pretty confident that THIS is the cause and solution.
Senior Member
Join Date: Sep 2006
Location: N.E. Wisconsin
Age: 70
Posts: 1,984
Likes: 0
Received 0 Likes
on
0 Posts
re: How to Repair Relay Control Module (RCM) - (Mystery no Start)
Originally Posted by pizzaguy
180:
I see this all the time in both Motorola and competitive equipment: they use the MINIMUM amount of solder to build the assembly.
They teach you to "not depend on solder for physical strength, always tie down and secure connections, boards, etc."
Which is stupid, cause....They also teach you to use the minimum amount of solder that will "do the job".
I spend a LOT of time resoldering broken connections in radios, sirens, lighting control boxes and other crap we put into police and fire vehicles. I must say, some stuff STILL comes back in a few years, no matter how much solder I use or how hard I try to "make it right".
But the fact remains, if you flow enough on there like in tight's "Me So Horny" modification pictures - you WILL have less trouble.
I see this all the time in both Motorola and competitive equipment: they use the MINIMUM amount of solder to build the assembly.
They teach you to "not depend on solder for physical strength, always tie down and secure connections, boards, etc."
Which is stupid, cause....They also teach you to use the minimum amount of solder that will "do the job".
I spend a LOT of time resoldering broken connections in radios, sirens, lighting control boxes and other crap we put into police and fire vehicles. I must say, some stuff STILL comes back in a few years, no matter how much solder I use or how hard I try to "make it right".
But the fact remains, if you flow enough on there like in tight's "Me So Horny" modification pictures - you WILL have less trouble.
Ain't THAT the truth, Mark!
As you, I've lost count as to how many boards I've had to resolder because of lousy factory jobs.
180 - ALL modern PCB's are soldered by machines. Waaaaay to costly to do it by hand.
Tighed - EXCELLENT post. I can now see all of us out here yanking our RCM's for a little preventive maintenance!
THANKS!!!
re: How to Repair Relay Control Module (RCM) - (Mystery no Start)
Good kill. I offer up a WOODY award for that one.
Didnt wanna stiff you, good work.
Annular solder cracks are often due to thermal expansion and contraction stressing the minimal solder joints.
Me I make nice round ***** of solder, for strength.
Woody
Didnt wanna stiff you, good work.
Annular solder cracks are often due to thermal expansion and contraction stressing the minimal solder joints.
Me I make nice round ***** of solder, for strength.
Woody
The following users liked this post:
BrushRoadster! (03-18-2022)
Join Date: Jun 2009
Location: Fort Worth, Texas
Age: 64
Posts: 13,450
Received 880 Likes
on
686 Posts
re: How to Repair Relay Control Module (RCM) - (Mystery no Start)
Originally Posted by Kurts
I can now see all of us out here yanking our RCM's for a little preventive maintenance!
We need a gun with new tip, solder, few hand tools for keeping the tip nuts tight, a smoke vacuum with filter (if we are doing this indoors) and maybe a 100 foot cord (if we are doing this outside).
I have all the above in my bag of tricks, and think I can squeeze it all in the trunk, since it looks like top-up weather (due to cold, if not rain).
What do you all think? Could keep us busy - or should I save the room for my costume for saturday night?
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.