SHORT IN ENGINE

My 1990 ford bronco 2 indicates a short when I check between the neg posi and the removed neg battery clamp. This shows a full 12 volts on my voltmeter. When I remove the 30 amp fuse from the fuse blocks under the hood the short is gone. I removed the eec relay and relaced the 30 amp fuse and the short appears to still be there. According to my haynes electrical schematic a yellow wire runs to the eec at kapwr[?]. If oi leave all the fuses in and the battery connected I do not show a battery drain if I leave it alone for a few days. If I run the vehicle and let it run the battery will go down. I have relaced the brushes in the alternator along with the voltage regulator. My dash voltage gage will go from a stopped position to the far neg. Left to mid way between far left and center of the gage, this is not positive voltage.I do not know how or where to test the eec for faults or errors. I believe that my eec is located on the drivers side in the vehicle near the rear seat. I am on a stand still on this. Any help?Also my check engine lite goes off when I start the engine.