Thought i posted this last night... iphone never sent it [Ok so I pulled out the wire diagram. I know the heater circuit is good. I stripped all the tape off the harness from the PCM to the connector and it was good wih no visible damage and it was all secure. So I looked at the o2 extension again. I know I checked for continuity and resistance on each matching pair of wires. But I didn't check for a short! It is the extension all along. I have it in my lap right now. There were three wire ends that were not in the solder joint that got thru the tape and must have made contact with another wire. Time to make dinner as I haven't ate all day. Will install it later tonight or in he morning. Wish me luck that this was the only issue.
On the bright side of things, I got a new oxygen sensor now and while I have the harness apart I rerouted the wires in top of the engine for a cleaner look.]
Thank you bill for your help. knowing that it should read 450 with it unplugged helped me to eliminate other variables.
