I know this is a 2 year old thread, but I am having the same problems so I thought it would be best to keep the possible solutions in one place.

2005 SRT6, garage queen (3500 miles per year if that), gets the charger put on it every couple of months to keep the battery up. Have had no problems until May this year when I got what I thought was the RCM solder problem.

Battery is 6 years old, posts have been cleaned and clamps have been tightened. Battery charger is on it and set to 10/30A charge.
Turn the key, all dash lights come on and starter will not engage 99% of the time.
Like the OP, I was holding the RCM once when my helper turned the key and it started, so I though bending the board had something to do with it. Shut the car off and could not get the starter to engage again.
Sent the RCM to DJ for a full rebuild. He said it worked when it got there, he rebuilt it (changed relays) and tested it in one of his cars. It still worked so he sent it to me. Starter will still not engage.

Now for the questions:

Even though my battery is 6 years old, will keeping the charger on it while I am trying to start it overcome that? I know these cars are quirky when it comes to voltage but the day it died it started just fine (cranked over good and strong), I drove it for about 30 minutes, let it sit for 4 hours and then the problem began. So, I was hoping that rather than throwing a battery at it and being no farther ahead, I would save the money until I can figure it out.

Looking at the Starting Circuit diagrams, can I run a 14GA jumper wire from the positive battery post to connector C106, Cavity 6 to see it the starter engages so I can rule out the starter?

If the starter engages with the jumper, working backwards in the diagram, I should see 12VDC at cavity 6 on the mating connector of C106 when the key is turned to start, correct? That is with the positive lead of the DVM at the connector and the negative lead on the ground point for the battery.

If I see 12VDC there, then I assume the starting circuit is good and maybe I'm not getting enough current and I need a battery?

If I don't see 12VDC there, then I move to the Pulse Module, Connector F, position 1 and see if I am getting 12VDC output from the module. If I do not get 12VDC on the output, time for a Pulse Module, correct?

Should everything be 12VDC in this circuit?

Thanks in advance for your time and comments.

Randy