Probable Grounding Issue. Help With Where To Check?

So, for a while now I've had suspicions that my LGT has grounding issues. Pretty consistently, turning on my headlights causes my AccessPort to lose communication with the ECU, I get headlight flicker at times and my seat heaters seem to be off and on.

Today, however, things went to a whole new level. As I was driving, my Valentine 1 kept turning off and back on. At the same time, my nav system kept rebooting. And finally, after I had stopped and picked up some dinner for the family, I came back to the car and it's behaved as though the negative battery terminal had been disconnected and re-connected. No radio stations stored, no date in the nav system and the car started like it does after an ECU reset.

I understand that I really need to check all the grounding for the car, but am looking for a little help as to the locations. I'm aware of the grounding straps from the engine block to the frame rails, but know that there are several other major grounding points where I should check. I even have looked through the factory service manuals, but there's no 'quick reference' page listing all the primary grounding locations.

Thanks in advance!

http://legacygt.com/forums/showthread.php/car-had-hard-time-starting-244590.html?t=244590&highlight=ground+upgrade

http://legacygt.com/forums/showthread.php/ground-straps-bottom-engine-206442.html?t=206442&highlight=radio+static

page 5 of second link buy kit from JMP, i made my own long time back, should be first thing on all legacy!

Start by checking for corrosion on the battery cables/terminals. This happened to me on my '08 3.0R until I finally broke down and replaced the terminals to the battery.

Even if they look good from the visual inspection disconnect them and look for corrosion on the mating surfaces.