Thanks for the reply, I'm afraid that i'm not too experienced with electrical stuff, I did find the tech job aid manual and I found the section about checking continuity but I don't quite understand what you mean or how to test to make sure I have those readings.
I do have multimeter, but do I leave the machine plugged in? turned on?
I did test the blue wires that plug into the motor control unit and got a reading of 5v DC, but the manual I have says that those wires are the serial comm link?
I unplugged both the power supply and the motor connector plugs off the MCU and checked them for ac, but I didn't get any readings. All of this was with the machine plugged in and turned on.