Tripac apu short on fuel solenoid

I have on my tripac a short on the fuel solenoid, as my first guess I changed the solenoid to a new one but didn’t fix nothing, I can’t connect the 40 amp fuse on the F7 in the interface board or a short will blow fuse or will heat up the positive cable on the batteries If I disconnect the fuel solenoid nothing wrong shows up, I have traced the wires on this circuit wires 8DP and 8D and cant find any breaks or shorted out to ground, as soon as I connect the solenoid again same issue, can anyone direct me in the right direction as to where else to look for or what else to check, I checked the voltage on the 8D wire on the harness connector where connects to the solenoid and it’s showing grounded but like I said I couldn’t find any faults on the wires and I have checked the entire harness, tried to check the RUN relay but can’t pull it out, any help would be greatly appreciated

 

Thanks for the reply, yes I have disconnected the fuel pump and tried it but still same issue.. Update: turned out to be the interface board, not sure what its called but its like a chip that theF7 fuse is connected to is burned, looked at it closely and at the bottom of that chip has burned damage