Matt;

Congratulations on finding an resolving the stereo power problem...

...but why on earth would you just ground a loose wire without any better reason than "Being the trial and error type"...that's not smart!...the smart thing to do would be to look at a wiring diagram, like at: http://www.intelab.com/swem/122S%20Wiring%20Diagram.jpg ...where you would see just from the color code, that a white wire is likely one of the wires having to do with supplying "parking light" power from the light switch to the parking lights (or instrument lighting dimmer) by way of Fuse 3.

The wire may have come off by accident(?), or may have been removed for a reason...check it out(!), before grounding it (and don't ground it at all!), unless you own stock in a fuse company!

When you find loose wires around the house, do you "just plug them in, to see what happens"...just wondering?

Cheers