2005 Ram 2500 5.9 Diesel. Hello fellow truck enthusiasts. I recently got done overhauling the motor after a piston problem occurred. When I was putting the engine harness back on I accidently hooked the negative grounds of the harness to the positive of the battery thinking that where it should go. When this happened the fuel pump started priming and wouldn't turn off. I realized that was not the right spot and found out it goes next to the grid heater as a negative ground for the ecu. After solving this, I turned the key over for the first time. Right away,)no bus) came up, my headlights came on and wouldn't turn off. I had no control over anything other than the blower motor. I checked all my connections and made sure they were not corroded. when I unplug the ground for the harness, I get all my functions back. I can use my headlights, wipers, horn, ect. I left the ground pluged in and found that if i unplug the right connector on the ecu I get my functions back, but when its plugged in the truck seems to lock up on me, I tried a scanner on the system, but it wouldn't connect to anything. What are the odds that the ECU whent bad after a rebuild like this? Could it be in the harness? is there a test I could perform on the system? I am really just looking for advice because this was supposed to be on the road last week. Any help would be greatly appreciated!

center wire next to heater was connected to battery positive for a while

 

You could have fried some stuff…..But have you checked to see if you popped any fuses?

 

Yes i have checked that and all fuses including the one under the dash check out