crazy gauges

Everything works off a ground. (except the speedo of course) Make sure you have plenty of grounds, thats something you can never have enough of.

For instance. My battery is in my trunk...

I have a 1 gauge cable directly bolted to the frame.
2 gauge cable from the terminal to the body.
10 gauge from the battery to another part on the body
I run a solid motor mount on the drivers side that doubles as a frame to motor ground
I run a 1" thick braided ground strap that ties the motor to the body

Needless to say, I have no grounding issues in my car :D...Check your groundS