Well dont I feel dumb A + D check out fine. But B shoots up to 100mV and then drops to in the 90s, then just fluctuats in the 90's but not to wildly.

Going to check the opit and related wiring right now. Would a bad opti cause the BCM not to provide ground to the theft deturrant relay and not let the car turn over?

 

I am a bit confused. Engine would not crank...removed battery and reinstalled 48 hours later...bypassed unknown relay...now car won't start. I guess I would have to agree with the post that suggested returning to the basics, like why won't it even turn over without bypassing relays. I personally would address the no crank problem first and then the no start problem.

 

I belive they are related. The car will not crank because I am not getting the ground from the BCM to the Theft deturrant relay. I was hoping that its just a wiring problem or some corosion somwhere rather than a burntout BCM. The day i started having problems the temp dropped to 10 with -15 windchill.

 

Sounds like you are on the right track. It sounded like you were getting a little bit ahead of yourself at first but I probably just misunderstood. Sorry I can't offer more help but I'm sure if you listen to some of the old timers on this board they will get you going again. Good luck.