electrical ground problems

ok, I've got the problem with my 97 wrangler traced back to an electrical ground problem, but can't figure out what the cause is. All of my brown w/ yellow stripe wires coming off of the coil, camshaft sensor, throttle body sensor, fuel sensor, oil pressure sensor have bad grounds where my test light barely glows. The engine will crank over but not start. If I ground out the brown/yellow wire (any of them) with the test light I can start the jeep, but it immediately dies if I unground it. All of these wires seem to lead back to a ground sensor in the pcm. soooo.... what exactly is the ground sensor in the pcm? Is my pcm no good and not grounding all of these components? Or is there a problem somewhere else? I've checked all of my main ground cables and they are good. Hopefully somebody has some info on this--I'm ready to get back on the road. :banghead:

First place I'd look is the negative battery cable, check both ends. Then check the positive side; I've seen positive cables that look ok on the outside, but are turning to powder on the inside.

Edit: check both ends to make sure they're secured properly.