Ignition coil problems

i have a 87 911 porsche. the coil is getting power at the 15 terminal and the 1 terminal also, as verified by the dealer. the ohm reading is 7 across the 15 and 1. what i dont understand is, how does the coil get negative to the 1 terminal which is marked negative on the coil. does the computer make it a negative signal and if so, (which it is not doing with mine) what would cause the computer not to send the negative signal?


Any help would be nice :)

All the relays are changed, and i have two computers which are doing the same. The alarm system is faulty, but only for the fuel pump power which i by passed. According to the service manual, the ignition has nothing to do with the alarm.

The DME grounds out the #1 to make the spark. Meanwhile, you will be reading 12V through the coil since there is continuity from #15.