Looking at a Cat 520E that the backhoe and outriggers do not work. Looks like the fuse is blown. I am thinking that the lockout solenoid or its wiring may have an issue- Where is the solenoid and how do I get to it? Thanks!
Don't you mean 420E.? Either way please post a machine Serial Number so that we can find the appropriate electric schematic.
You are right--- 420E is the model 0420EEHLS02157. Thanks for the response.
Check your messages for an electrical schematic. Attached is the diagram for fuses and relays.
Fuse P20- Ride control and Hydraulic Lockout blown. What/where are the 2 components associated with the ride control and/or hydraulic lockouts located? I am thinking there must be some sort of solenoid or actuator that gets direct power from a relay not actually the switch?
From looking at the electrical schematic fuse P20 supplies keyswitch power to both the diff lock and ride control relays, then it also powers a plethora of other circuits via wire 143-PL138-BR. You'll need to start tracking each of them down to find the problem. Pulling the two relays first might be a quick way of eliminating them.
After doing more checking it does not have a ride control switch, I don't think the diff lock gets used much, that leaves the hydraulic control as the most important circuit. Circuit PL 138 feeds others according to the diagram, blue wire. I am assuming when the lockout is used, which may be often, that is blowing the fuse. Looking at the diagram it seems that the N939 PL107 has to be switched on for ride control,but dif lock is always hot, where 30 feeds 27a in an unenergized position?
That is correct. Any wire drawn in BLUE on the schematic has battery voltage when the key is ON. Any wires drawn in thick BLACK are ground. The ride control relay coil is pulled in via wire 976-OR (to relay pin 86) when the ride control pressure switch (also supplied with switched batt+) contacts close. F738-WH from the Ride Control relay Pin 85 completes the circuit back to the Machine ECM.
Looks like when the hydraulic lock is applied from the rocker switch the fuse blows. So I have a shorted wire going to what I assume hydraulic solenoid, or that solenoid is shorted. Where is that solenoid located, and how do I get to it? Thanks!
You're talking about the implement lockout switch, correct.? That doesn't operate a solenoid. It simply gives a signal to the Machine ECM. if you trace wires E917 & E918 they both go to connector J1 on the Machine ECM, Pins 63 & 64 respectively.
I traced the short to a 2 pin/2 wire connector under the floor plate. Connector 46. According to my schematic that goes to the return to dig /parallel lift system. I am not sure if those are options, or how to tell if they are part of my unit. Unplugging that connector doesn't blow the fuse and lets the backhoe work again. Any ideas on this part of the unit? Must be getting close!
They are not options. Every machine will have a return-to-dig system fitted, whether it is parallel lift or single tilt. it's just a case of which one. I would suggest that your next move should be reconnect CONN 46 then unplug both the joystick base (6-pin connector) and the bucket position sensor (3-pin connector) and check if the fuse still blows. if it does you have a wiring problem. If it doesn't one or other of those components is the cause.
Looks like I will leave that connector unplugged to get the unit back in service. I can't seem to be able to sensibly trace that wire. It goes into a big harness that is buried under the floor area. I will keep trying, but I did get it working with your help and --THANKS.
PS I will be working on finding the bucket sensor & joystick base wiring, but it can be used as is if needed.
It is Ref #9 on the attachment. Although the graphic doesn't show the exact route it may give you some assistance in at least finding one end of the harness.
After trying to locate and trace the wiring, my massaging the wires, must have done something , now the short is gone... At the connector where the short could be eliminated, when it was shorted, I will try to power up the previously shorted wire with a separate circuit using a relay and fuse. If it shorts later, at least the backhoe operation will operate. I did find 2 wires at the front loader bucket that were yellow and orange which seemed to be powered by the original circuit. Will respond inf anything else shows up..