LS3 connect and cruise in 68 cutlass has electrical starting issues after 7K miles

[68conv455]

I've had a good experience with my connect and cruise LS3/4L65E but now have some weird electrical issue preventing me from starting the car.
Any suggestions would be appreciated
Here's what happens:
Turn the key to run, speedhut gauges cycle, fuel pump runs, then I turn the key to start, the starter blips for a second and I loose all power to the dash.
gauges go dead, no fuel pump no headlights. Nothing at all when I turn the key a second time.
After waiting (a while), same thing followed by a completely dead car. I feel like there is a fuse somewhere that resets then trips again.
battery is good
Power direct from battery to GM fuse box is good
Power to horn relay is good
I assume there is an issue somewhere between the firewall to ignition switch to the starter
Car has only been pulled into and out of the garage since fall when I work on my other car. No issues till yesterday. I use a battery tender.
Any thoughts?
Thanks.

[dhutton]

Have you got one of those Ididit steering columns with the relay?

Don

[68conv455]

stock steering column

[csouth]

Sounds like weak grounds to me. The ground could be good enough to do all the things you describe, but not strong enough to turn the starter over.

[Hotwire]

Check your battery connections to make sure they're clean and tight. If you are still running the stock wiring harness you might need to pull the fuse box off the firewall and clean the connections between it and the engine bay bulkhead.

[68conv455]

Thanks.
Things I will check next:
Ground from GM fuse box.
Connections at ignition switch.
Connections at starter.
battery connections already checked

[oleyeller]

Replace to starter relay if there is one, and replace the ignition switch. That's where I would begin.

[TANKMASTERJ]

I never replace anything until the problem is found. With any automotive or heavy equipment type application, if something works then don't. It's 99% of the time bad grounds. I have seen ground fault in ECUs but its rare.