Background - Went to get gas, start up was usual, got gas, turned ignition on, nothing, radio reset, lights slow to come up.
Tried jumping with three different vehicles, starter just clicked, radio kept resetting, headlights off until jumpers in place. ( I just wanted to check, no I didn't try to start with them on)
Pulled terminal connectors, no corrosion no breaks. Called tow truck, replaced connectors, tow truck driver had boost pack, tried that started right up, he said volt was reading high on the boost pack meter..
Battery charge display on speedo read normal high ( usual sits around a in normal now pointing l) fluctuated between a and l the whole ride home.
No light dimming, Ran normal the whole way home.
Turned engine off in driveway, turned ignition on, same problem as at the gas station.

Woke up, grabbed mutimeter, disconnected terminals again, wire brushed terminals and connectors even though they were clean reconnected wires to battery.
Open door dome lights off, slow build to a dull glow, turn on ignition everything drops out.
Put multi on battery reads 12.7 ignition off, then drops to 3.5 with ignition on.

New battery or am I chasing a short (shivers)

Thanks for your time.

 

You've got a bad ground. Check the negative battery cable and where it's bolted to the frame

 

First off, thanks for the reply.
I can't see where this damn ground is, not from top not from bottom, not anywhere.
I traced the wire cluster (great word for it, it's just missing it's last name, the one that starts with f) to the passenger side where it splits, one section going to the alternator,
the other going (disappearing) between the engine and the mount (can't see anything through the mount) terminating at the starter.
I tried jumping from the negative to the engine block directly with my jumper cables still nothing.
Opening the door the dome light does a slow fade to on, turn key, with or without the jumped ground, and everything drops out, no dome light no dash activity, nothing.
Could there be a fault in the battery itself that it reads good voltage (high 12's) and is garbage under load (3.5v)? or am I chasing a bad relay?

 

It is possible the battery is actually dead. The open voltage doesn't mean much; it's the voltage under load that matters. Do you have another battery to test with?