Been reading through a tremendous amount of posts here and on other forums... mine does seem to be a little different though.
I'm probably including too many small details, but I don't want to miss what might be an obvious clue...

2003 Z06 94,900 mi.
Short back story... Bought the car from a forum member 11 years and ~50k miles ago, details in my signature. It's been nothing but a joy. A couple of small electrical issues I was able to handle.
Replaced original suspension with coil overs. Never left me stranded or failed to start. Love this car. It has occasionally shown Service Column Lock and Pull Key, but never failed to crank or start or shown any codes. Previous owner had the locking plate removed and it appears the Relay has been removed as well.

Fast forward to current... about 4 months ago, driving on a beautiful day (briskly), engine died, dash went black. Coasted into a bank parking lot. Battery showed 12v, but couldn't get anything to energize, checked all connections and possible culprits I could without much more than a screw driver and testlight, but nothing. No Crank, No Flashers, nothing.
Had AAA flatbed it to my house. Put the car down on my driveway, tried it 1 more time and it started. Didn't get it all the way into the garage and it died again... this time dash stayed lit, plus service column lock and Pull key... alternatively on retries.

Pulled codes and all I got was Crank Position Sensor. OK, makes a bit of sense. Ordered and installed after a 2 month break for surgery (on me). Long tube headers made the job much more difficult than it should have been. Replaced solenoid and starter after the small purple wire stud snapped due to corrosion and heat bake from the headers.
The day I got it all reassembled, I tried starting it and no crank, all dash lights went out. Turn key off and wait 10 minutes, same thing. Checked battery with multi meter and showed 12.79v at rest, 11.1v while cranking. Pulled it anyway to get it load tested and showed 800A. So it's good. Checked grouds at block, and other points in the interior, all good. Checked battery cable and got unsteady readings. Neg cable at side post was kinda wobbly, checked it, threads looked bad so I put new side mount bolts in them. Dash lit with Column lock and pull key messages but car fired up in 1 click.
Subsequent tries yielded security light behaving normally, alternating Service..., Pull Key... and no crank.

My research led me to start checking VATS, TDR and Ignition switch. Yesterday, I cleaned the resistor pill on both of my keysets and sprayed the Ignition switch with contact cleaner. First try after, I got Pull Key and service column lock, but it started on 1st click. 2nd try, I only got service column, but no crank. Immediately cleared the message and it started. The next 10-12 attempts same thing... insert key, turn to run, wait for gauges to sweep, clear service column message and it starts. Then, it doesn't... So I'm assuming my next move is to bypass the Vats with a resistor at the steering column and a LMC5 kit. Fine.

Pulled codes and get nothing related to this at all.
BCM 0502
BCM 0507
BCM 2482HC
HVAC U1160H
SCM U1255H
I surveyed the BCM and fuse box area and found some cut and spliced wires (some unwrapped) that I wasn't expecting. I know the previous owner had a shift light and aftermarket CD changer in the trunk both of which he removed prior to the sale. Do these look like that's what they could be associated with? I want to make sure that doing the bypass and LMC5 won't add to my issue in any way.
Pics attached.


Footwell as found


wiring exposed

'03 Z06 - Black
Comp Cams 281/283 .595"/.598" 112 deg. XFI/XER Cam
LG Longtube Headers with high-flow cats
Vararam cold air
B&M Ripper shifter
LG GT2 Coilovers
Drilled rotors, Hawk HP+ brake pads
Sumitomo HTRZ lls

 

My car recently went from first crank to absolutely dead. No lights, no buzzes, nothing. Two turns of the key, one spun the motor, the next did not. Looked at all the associable threads I could find, both through the search here and on google. Battery showed 12.4 volts on the cable bolts. Based on information from here on the forum, I pulled the battery side terminals, found some corrosion on the positive terminal bolt, and a curious lack of indentation from the cable terminal into the battery terminal. Cleaned all the terminals and bolts, re-attached -- with more torque on the fasteners than ever before, though I doubt a full 11 pds/ft, and it cured my issue. Well worth a quick try -- maybe a half hour to do all the above?
Post #4:
https://www.corvetteforum.com/forums...a-battery.html

 

Thanks. Yeah I did all that. In my dense paragraph of info I told of replacing failing side post terminal bolts...
I appreciate the info...

 

Apologies for missing the battery work. I do not know how I did that. Now it reads like the loose ground cable -- mine was the ground as well -- may have instigated the service column lock issue. I already had an LMC5 when the cable wriggled loose, so did not have that issue. I would agree with installing the LMC5, possibly going straight to the brown wire mod, as defined in the instruction sheet.

 

Just ordered it. We'll see how it goes. I'm pretty confident that's all it will take.

 

I agree with rezg regarding going straight to the brown wire mod. No sense not doing it while you are in there.

 

Could someone please post the actual instructions on installing the LMC5 with the brown wire mod. Mine has one with out the brown wire mod and I want to do it, seen many videos but would really like to be able to see and read it. Thanks

 

If you have the earlier version, before the brown wire, I suggest you contact Compliance Parts... They can help you out.

 

This has the brown wire loop, just not cut and installed

 

Mine arrives today, I'll send you a pic of the relevant instructions...

 

Thank you so much !

 

Here you go, good luck.

 

Got it ! Thank you so much, let me know how it goes and anything I should know when I do it. And if you have any problems getting the connections off and the brown wire installed in the proper whole
thanks again

 

Deal