420E IT BackHoe Loader #KMW01023 I'm having trouble with my lift pump. The pump, relay, and diodes have been tested and are working properly. Where I'm at now is I turn the key to the run position and the "org wire" only has 0.60 volts. Where should I look for the power source for this "org wire"? I'm assuming the orange wire should have a 12v in the run position?
At x977 do you have power
To be exact, there is 0.01 volts on x977
I'll send you the complete electrical schematic. Check your message inbox. FYI the power on wire 307-OR comes from the FNR Shift Handle. As I see it the power to pull in the fuel pump relay comes via 307-EF40, through the diode to the realy coil via X977-EF57 & X977-EF54. Once the relay coil pulls in battery power from 123-EF18 goes via X977-EF56 and X977-EF8 to power up the fuel pump.
Nige, very helpful, thank you. With the key is in the run position 308-PL278 has power (12volts). With the shifter in the neutral position. Is there any reason I would not get power from 308-PL278 to 307-PL163?
That is expected. 308-PL278 is energized by turning the key switch to the ON position. That's why it's drawn blue on the schematic. I'm sorry I don't know the answer to that. I'm not familiar with the principles of operation of the FNR Shift Handle. You could try a couple of tests with the key ON. 1. Disconnect the power to the starter motor then turn the key to the START position. Does 307-PL163 power up.? 2. Supply power externally to 307-PL163 and see what happens as regards the presence of power at the lift pump.
I'm surprised, yes it powered up the lift pump. Yes, the lift pump powered up and started pumping. Thanks for the suggestion, that saved me time and a good chunk of cash. There is nothing to fix, it's not broke. So quick story time. I recently inherited this 420E IT. So I'm doing the maintenance, change, and check fluid levels. I changed the fuel filters I thought I read somewhere that you turn the key to run position for 3 minutes and the filters would prime and I would be good to go. The prime/lift pump would not power up when the key is in the run position. But now I understand that when I need to prime the fuel system, I need to bump the starter and don't start the engine, leave the key in RUN position, and wait 3 minutes for the filters to prime. Thanks Nige
Maybe the attached will shed some light. If you don't already have one I cannot recommend strongly enough that you get hold of an Operation & Maintenance Manual for the machine. An Adobe pdf copy can be downloaded from HERE . Put SEBU7687 in the box and click the Search button. The image below should appear. Downloads are available almost immediately once you have paid for them. A cheaper option for genuine OEM manuals is HERE but unfortunately they are only available in paper or CD formats. Add S&H charges to the prices shown.