I have a 420E backhoe that has a voltage drop to the back joysticks its a 12v system and im only getting 3. The joysticks control the jackhammer and the boom slide neither will operate. I have already checked the ground to it and it is good and i gave the solenoid direct power from battery and it worked. any help with this matter would be greatly appreciated.
When you measured the voltage drop I assume you went across the positive and negative wires at the joystick WHILE the system was in use and you measure 9 volts. If you unplugged it and measured across it you are measuring potential across an open circuit. If that measures 3 volts you have a major corrosion issue somewhere. With electrical diagnosis you always try to cut things in half. First step is to figure out if your problem is on the ground side or the positive side. This is easy to do. Once you know which side of the circuit is giving you a problem then find a connector somewhere else in the circuit and test there. If good then the issue is in the section you just eliminated. If not, then find the next connection and do the same. Sometimes some connectors are hard to get to so you might test at the easier one first. Post a copy of the wiring diagram you are using so we can help you.
Serial Number gets you an electrical schematic.
That would be awesome thank you. Its DAN01164