Badland Part 103 Pilots and Builders Forum

Kind of puzzled here. You said one wire from the engine harness goes to the push button switch and the other side goes to ground? That seems bassackwards to everything I thought I knew. My opinion is that is why the starter engages when the battery is connected. The push button is just a momentary switch to pass the circuit through on to whatever. Generally the power wire would go to one side of the switch and the other side would go to the starter relay to engage the starter. I would do my best to verify the correct wiring before any damage is done. Just my worthless hillbilly opinion.

According to the almost worthless Polini schematic, the yellow/ green wire runs from the relay to the starter switch which when depressed connects this wire to chassis ground.

I did find that my pushbutton switch was back-assward... grounded then open when depressed. HOWEVER, the starter motor engages as soon as I connect the battery even with the starter switch REMOVED.

I must have a ground somewhere in the circuit. Driving me nuts.

I guess Peer and I were lucky. The 303DS is a plug and play system. Good thing, my street italian is pretty bad. And you are correct about Polini's wiring diagram. If you could call it that.