299D No Auxiliary Hydraulics

[Nige]

I had it running.

Well that rules that out then...........

If you follow Wire #127 back on the schematic it comes from a dedicated 10A fuse in the fuse panel marked "RH J/Stick Base". Maybe the output side of that fuse should be your next port of call.?

 

[Jeffrey Bandel]

I'm curious what this switch does? The one with the rabbit and aux on it. I don't have the operator manual in front of me but the repair manual doesn't show it. I have pushed it both ways with no results.

 

[Jeffrey Bandel]

Well that rules that out then...........

If you follow Wire #127 back on the schematic it comes from a dedicated 10A fuse in the fuse panel marked "RH J/Stick Base". Maybe the output side of that fuse should be your next port of call.?

10-4

 

[Jeffrey Bandel]

Wire 127 in CH-C3 has power at the Deutsch connector under the arm rest. I checked it yesterday. Wire P984 in CH-C2 also has power.

 

[Nige]

At CH-C2 look for power on P769 YL. It is power supplied from the ECM so you will have to use wire P770 WH (Pin 2) as the ground, NOT machine frame ground. Should be 8V.

What voltage did you measure in Wire 984.?

 

[Jeffrey Bandel]

no power on p769. 13.8 volts (grounded to frame) on 984

 

[Nige]

no power on p769.

Was that measurement made with the Aux Hydraulics "activated". I am not 100% certain but I suspect that power will only show up on P769 if the Aux Hydraulics have been requested.

 

[Jeffrey Bandel]

I'm trying to figure out how to activate it. Is it the switch I post a picture of?

 

[Nige]

I'm curious what this switch does? The one with the rabbit and aux on it. I don't have the operator manual in front of me but the repair manual doesn't show it. I have pushed it both ways with no results.

That is the 2-speed/AUX 7 control. The purpose of AUX 7 is to provide electrical power to Pin A on the loader arm connector.
Push the top of the switch inwards then use the trigger on the LH joystick to control 2-speed.
Push the bottom of the switch inwards then use the trigger on the LH joystick to supply electrical power to Pin A on the loader arm connector.

 

[Jeffrey Bandel]

Got it. But is there a switch that controls the aux hydraulics I need? People have mentioned it but I don't ever remember hitting a switch?

 

[Nige]

Got it. But is there a switch that controls the aux hydraulics I need? People have mentioned it but I don't ever remember hitting a switch?

Not that I can see. This is the best explanation I could find for engaging the AUX hydraulics.


When thumb wheel (29) is moved, pilot oil is directed to the auxiliary circuit spool located in the control valve. Thumb wheel (29) is a proportional switch. Move the thumb wheel slightly for a small amount of flow to the auxiliary couplings. Move the thumb wheel further in order to obtain a higher flow to the auxiliary couplings. When a high flow work tool is detected by the ECM at the work tool electrical connector, and the thumbwheel is at 100% the switch will trigger the high flow mode giving maximum flow. Refer to "High Flow Mode" in this manual.

Move the thumb wheel forward in order to increase the flow of oil to the male "Aux 2" coupling. When you move the thumb wheel (29) forward, the ECM activates a solenoid allowing pilot oil from gear pump (charge oil) to activate the AUX spool. Supply oil from the piston pump (work tool) flows through the spool to the male "Aux 2" coupling. Oil from the piston pump flows through the work tool circuit and retiurns through the female "Aux 1" coupling to the spool for the auxiliary circuit. The oil then flows from the control valve (work tool) back to the hydraulic oil tank.

Move the thumb wheel backward in order to increase the flow of oil to the female "Aux 1" coupling. When you move the thumb wheel (29) backward, the ECM activates a solenoid allowing pilot oil from gear pump (charge oil) to activate the AUX spool. Supply oil from the piston pump (work tool) flows through the spool to the female "Aux 1" coupling. Oil from the piston pump flows through the work tool circuit. and returns through the male "Aux 2" coupling to the spool for the auxiliary circuit. The oil then flows from the control valve (work tool) back to the hydraulic oil tank.

 

[Jeffrey Bandel]

Yep. That puts me back to the beginning. The thumb wheel is not getting voltage.

 

[Nige]

That puts me back to the beginning. The thumb wheel is not getting voltage.

Try going back along P769/P770 from C-CH2 towards the ECM and look for voltage on P769 using P770 as ground. CONN 13 is one major harness connector betwee the joystick and the ECM.
The schematic shows the locations of the major harness connectors.
P769/P770 feed a number of functions (track motor speed sensors & ILEV cystem) not just the roller switch.
I think you might have a wire break in a harness somewhere, possibly between Conn 13 and the ECM. I can see a 5-way internal splice of both wires P769 and P770 on the schematic. See Grid D-14, illustrated below.

 

[Jeffrey Bandel]

No voltage to those wires on conn 13. Next is ECM I guess. The cab is in the air with the arm rests down and key on.

 

[Jeffrey Bandel]

The ECM is right next to the Conn13 and it looks like it goes into J2 but I don't see P769/P770 on the schematic of J2.

 

[Nige]

P769 - Pin 56
P770 - Pin 30
Both on connector J1.
I'll bet you find 8v between those two pins at the ECM with the key on - because you have no Active Diagnostic Codes for your drive motor speed sensors that are powered using 8v by the same P769/P770 wires.

 

[Jeffrey Bandel]

How did you find that!!! You are a genius. You must have this thing printed out on a 4X8 piece of plywood.

 

[Nige]

You must have this thing printed out on a 4X8 piece of plywood.

No. much easier than that. The pdf document is searchable. Put P769 in the Adobe pdf Search Box and then click either the Search Forward or the Search Back icon.
It will take you one by one to every location on the schematic that "P769" occurs.
If you want to find a wire in a specific harness (e.g. Harness "C") you could for example put "P769-C141" and it would only show you that wire.

 

[Nige]

If you find power between P769 & P770 at the ECM J1, your next step should be to find whether it is wire P769 or P770 that has the problem. Disconnect ECM J1 and CONN 13 then measure the resistance of wire P769 within Harness C between the two connectors. (J1 Pin 56 and CONN 13 Pin 42)
Repeat the process with wire P770. (J1 Pin 30 and CONN 13 Pin 43)
It is my opinion that one of them has to be open circuit (infinite resistance). When you find which one it is you could temporarily run a wire outside the harness from J1 to CONN 13 to replace the defective wire so that you can at least power up the roller and test it.

 

[Jeffrey Bandel]

I have no power at the ECM between P769 and P770.