Innova scanner not working 88 5.0

As some may know, the early Speed Density 86-88 5.0 cars did not come with a functional Check engine light. The 86 cars never had the means to display a CEL. The 87-88 cars do have a spot for the CEL under the tach, and part of the dash wiring. This, however, was solely for the 2.3L Mustangs

The pin on the ECU that matters here is Pin 17. On the '89 and later cars with a functioning CEL, Pin 17 would have a wire going to the EEC4 test connector and a wire going to the gauge cluster light. Pin 17 is a ground that the ECU can switch. By closing the circuit to the dash bulb, the...