u/Either-Friendship548

Hey I’m trying to help my father, I’m a novice technician that knows very little about electronics, but gets lucky constantly.

The old Control arm bypassed the brown ground wire connected to the tohatsu m90a motor to get it started, as a friend assumed the C.D. Unit was faulty. This worked, which surprises me, as every other wire that runs through the CD unit is not bypassed, and works perfectly once the bypassed ground is connected.

Now putting in a new side mounted control arm, I have reconnected the old ground wire, (now currently not bypassing,) and it isn’t working.
I’m wondering how I could diagnose this CDI unit, as I am not trying to splice or mess with a new side mounted control, in case of returning it.