Thread: How to Repair Relay Control Module (RCM) - (Mystery no Start)
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Old Dec 30, 2017 | 08:28 PM
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Radley
Joined: Dec 2017
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From: Massachusetts
Default Re: How to Repair Relay Control Module (RCM) - (Mystery no Start)
Being the diy guy I am, I decided to try my hand at this with zero soldering experience... the engine started turning over, but being -2 degrees didn't fully start. I tried again and it stopped rolling over and went back to the Whiney square one I started at. Would that be because I did a bad job soldering or was I fixing the wrong problem?
Originally Posted by tighed1
How to Relay Control Module (RCM) Repair - (Mystery no Start)
Click here to Go to post 120 for loaner RCM info
Thanks 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
6. Time for the repair. Get yer soldering iron nice and hot and (one at a time) heat the joint and apply additional solder. Be sure that the joint gets hot enough to thoroughly heat the pins that are protruding through the board. The pins are pretty stout and if not heated enough you may get a cold solder joint and end up having a starting problem because of that.

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!
 
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