Floating ground... is that what they use on boats?? kind of like a ground loop I guess. In welding we have a ground, and a workpiece ground. get them mixed up and those digital welders get crazy!!
especially when you get a new supervisor who wants everything to have a new shiny coat of paint, then complains when the welder doesn't work.

 

Digital circuits need a common ground because it is used as reference. A floating ground is unpredictable. The ECM provides a 0 reference and a 5 volt reference so the dital devices know what is 1 and what is 0.

 

alright you've lost me. What am I supposed to do?

 

Nothing, you'll live.

 

If I were you I would seal that lower connector. It is open at the top and could get water in it.
Wipe it off with acetone .. let dry, and use a good quality Silicone sealant. or sealing type heat shrink.

Silverfox

 

this is inside the vehicle

 

Condensation can still introduce water into that connection.

 

Alright I'll throw some solder in there or something

 

Pennies are not as good a washer as you might think as they've not been copper for many years. When the copper content made them worth more to melt than the were as currency, I believe they changed to copper plated zinc. Might not be zinc, but certainly not the best material for a washer.

In your situation it doesn't really matter what the washer's made of so the penny will work.

Ira

 

Here's some more pics. I finally added a fuse to everything (battery to alternator power wire, 4 channel amp, 12v lines running to the front for switches, etc)

I would like to add a box or make it look nice somehow but there isn't much room.

also I'm going to test the factory battery ground. I guess you just take a dmm and take one lead to the negative battery terminal and the other to chassis ground points and measure the resistance (impedance?) And I forget which number is better (lower or higher) but I plan to do this to a few spots where things are grounded.