The factory ignition setup looks like this.

In order to rewire the ignition to a pre-1983 state, the violet and orange wires from the distributor must be cut, and the orange wire from the computer to the ignition module too. Trace this wire carefully, as there are at least two orange wires in that bundle and you don't want to cut the wrong one.

Notice the violet wire from the ignition module goes into the connector, but doesn't come out the other side.

The module is under the washer reservoir, bolted to the fender.