I checked the fuses and they were all OK. While I had the box open, I took a look at the allegedly bad ME1 module and noticed that the right side (closest to the fender) connector was missing its metal bale. The left side connector had its bale and looked OK. There was also red electrical tape on the bunch of wires coming out of the bad (right) one. I removed the tape and also the black plastic cover of the plug, which I think was originally glued to it but now is loose.

Under the cover, I found two unions.

First one looks like it might be factory and is one green coming from the plug crimped to four identical green wires going into the bundle. The crimp looks like a vacuum port plug and is yellow. There is a strange amount of slack in the four geen wires though, as all the other ones run straight to the plug with no slack. Could these four be related to the four O2 sensors?

Second one is obviously NOT factory, as it was wrapped in the same red electrical tape as the bundle was. Took off tape and found a badly soldered (but probably solid) union between a red/green stripe wire coming from the plug and two identical red/green stripe wires going into the bundle.

Someone has definitely been in there, messing around for some reason. Is there normally any splices in the bundle under the black plastic plug cover? Would this show in any of the parts or service info? I am now hopeful that something external to the ME1 module is causing the module to look bad to the SDS. I just need to find out what the wiring looked like originally, and how to trace these suspect wires. Would this info (very detailed wiring diagrams) be available somewhere?