I am also excited about the new SD-45 locomotives.  I have been very impressed with new Bachmann locomotives.  I had switched to European HO scale trains and On30 trains to get reliable operation.   I have purchased 4 Bachmann locomotives this year and they all run very well.

I found the short.  The solder connections on the plug for the tender were sloppy, the wires for the negative motor connection and the left pick up were making contact.  I have removed the plug and circuit board form the tender, so I could hard wire the decoder harness to the wires from the locomotive.  Unfortunately the plug short damaged the decoder, so it has to go back to Digitrax for replacement.

I have been trying to install a Digitrax sound decoder in DCC ready Light Mountain I just purchased.   I have double checked all the connections to make sure there are no solder bridges between the solder points on the pc board, but the decoder still is detecting a short circuit and shutting down motor control.   All the sound functions and the headlight work fine but ther is no motor control.   I checked all the connections on the pc board and the the wiring harness but can not fine the short.   Does anybody have any idea where else I should look.