I guess your right, I think the circuit design is wrong. I have 3 transmission solenoids, all of them without diode, but one goes thru a relay and it's the only one not affecting my module. If I remove the relay and jump it, it does interfere. So now with all my testing I burned my new module, I'm waiting for a new one and the customer to modify the circuit. My solenoid have 2 wires if I want to install a diode, we're I need to install it? Inline on the positive side or across the negative and positive.