I'll try to look at my car, but going from memory, the loom attaches to the chassis in two places:
• The tail lights portion of the loom along with the fuel pump ground to the rear of the chassis near the fuel tank,
• The loom, battery, ECU, and engine ground to a stud welded to the top chassis tube where the transmission tunnel opens into the engine bay.
I had a really funky issue with my flasher circuit after the rebuild that turned out to be a bad rear ground wire. Turn on the hazards and the fuel pump would cycle on/off and the rear running lights would flash rather than the rear turn signals. Unplug a rear turn signal bulb, and the pump & tail lights would stop flashing and the remaining rear turn signal would work normally. Turn on the headlights or hit the brakes and a bunch of other weird stuff would happen. :banghead:
After much head scratching and trouble shooting, I finally ran a direct ground from the battery to the rear lights and the problem vanished. The permanent fix was as simple as replacing the ground wire from the tail light assembly. I hate electrical problems!
-John