I have a cat 247b skid steer mtl02314 My auxilary hydraulics started acting g up and then just quit. How do I test or figure out what's wrong. Please help Brenda
Are the Aux Hydraulics activated using the roller thumbwheel on top fo the joystick.? It is likely that the magnets could have fallen apart in the thumbwheel switch. See this thread for the latest updates. Enquiring minds are working on it but no solution as yet. HeavyEquipmentForums You can test the output from the thumbwheel switch with a multimeter. on your model.
Yes
It's a 2005 cat 247b mtl02314 skid steee
See my reply above. I edited while you were posting. Currently the only guaranteed repair option at this point in time is a complete new joystick handle.
How How Do I test with multi meter
Anyway to test and be sure it's the switch before buying new handle. I have voltmeter. Just don't know what to test
Disassemble the handle/armrest to expose the wiring coming out of the bottom of the joystick. Locate the following wires (Pins 1, 2, & 3 of the 12-pin connector) marked P994 Blue, P996 Green, & P997 Brown. With the connector shown in the schematic below still connected and the machine key switch in the ON position, back-probe and measure the voltage between P994 & P996. You should have 8v. If you have the 8v then measure between P996 & P997 (also whilethe connector is still connected) while rolling the thumbwheel from neutral to full forward and then to full reverse positions. You should get approximately the following values:- Centre - 2.9v Forward - 4.5v Reverse - 0.5v
Shouldn't it be between 994 power and 997 ground for the 8V check??
It should. Well spotted.
Nige- you are awesome and I am eternally grateful for you sharing of your knowledge wisdom. I purchased a new handle..problem solved e everything working great. Thanks again Brenda
I suggest that you should keep the old one. If we ever get a fix for replacing the roller switch it will be repairable. I am not a fan of a $500 repair to fix what is probably a $30 switch if you could get hold of one.
I just had the same issue on my 247B, after jerking the roller back and forth to unstick a load I only had extremely slow aux speeds working on my auger bit. Thought it was low hydraulic fluid, after that didn't work I found this thread. Quick workaround after reading it enabled me to finish the job by holding a large magnet nearby the thumb roller switch (took some experimenting to find best positioning) and then pressing the continuous button to hold the higher speed. The roller switch still worked sufficiently to disengage continuous operation. Seems a little disconcerting that arthritis gloves or similar magnets near the aux roller switch could cause it to unintentionally engage. Later when I had time I disassembled the joystick (you can use 7/64 allen bit if you do not have the T10 Torx handy) and opened up the roller switch by inserting sharp tool on each bottom end to unhook the 4 tabs on the base of the switch. Inside I found the magnet had badly deteriorated and bits of magnet dust were clinging like tiny strings of hair to the main body of the magnet. Thinking that they were distorting the magnetic field I cleaned them off but it worked even worse after (so do not try this at home!). Still looking for a small magnet I can epoxy into the old switch or a replacement switch.
See this thread, especially the last couple of pages. It may give you some ideas. Cat 226b thumb wheel switch replacement Has anyone found an aftermarket thumb wheel switch that works on a cat 226b skid steer it's on the right joystick . Mine has gone completely missing and the replacement is cost too much. Is there any alternative switch that can work in its place to get the auxiliary working again. Even the the... HeavyEquipmentForums
No aux hydraulic replaced switch still no hydraulic
Have you read all the posts above including the links, then done the required testing.? Machine Serial Number.? Which switch did you replace.?
I got same issue, but my machine sn MTL06116 doesn't have roller. it has only 2 push switches. checked with multimeter and I think it is a momentary switch. any idea what i should check next?
First thing I will send you the electrical schematic. You're going to need it. Then I suggest the following steps:- 1. Unplug the harness connector below the joystick. Test the wires for the push-buttons for continuity (or not) when you press/release them. Reconnect the wiring. 2. Go to the ECM and unplug the connector. Repeat the same continuity tests on the same wires for the push-buttons at the ECM connector. These two steps confirm the input signals to the ECM. 3. If the system passes all the above checks go to the AUX solenoid valve and apply 12v direct to it with the engine stopped. Do you hear it clicking.? 4. Do a continuity check for the wires from the ECM to the AUX solenoid valve. If everything above passes the relevant tests it would appear that the ECM is bad. A not unknown occurence.
Read Post #11 above and try again...............
Thank you so much for your help, I’ll check that, there are 2 solenoid valve on top of control valve. Which one is for auxiliary?
Actually both of them. They are referred to as A! (#3) and A2 (#2). One sends the oil flow in the AUX in one direction, the other one sends it in the opposite direction. That's what gives you a bi-directional AUX function.
makes sense, one last question. fuse box is missing cover/label. do you have a pic of it?
See attached.
I have 2.7v on 997 would this be a sign of a bad computer?
Can you post a Serial Number please. What is the problem that you have.? Unplug the 12-pin connector under the joystick and measure the voltage between wire 994 Blue which is power and 997 Brown which is ground.
The joystick all tests good
I have no auxiliary hydraulics
What tests did you do.? Still waiting for a machine Serial Number.
PDT01686
Thank you. So please can you do the tests below and post the results. 1. With the key switch OFF locate the 12-pin electrical connector directly underneath the RH joystick and unplug it. 2. Turn the key ON. Test the voltage on the machine harness side of the connector, marked R-C5, between Pins 1 & 2 (wires 994 BU and 997 BR). It should be 8.0 +/- 0.5v. Tiurn the key OFF. 3. Re-connect the 12-pin connector. 4. Turn the key ON. By back probing measure the output voltage between Pins 2 & 3 (wires 997 BR and 998 GN) with the thumbwheel switch in the centre postion. 5. Roll the thumbwheel all the way in one direction and measure the output voltage. 6. Roll the thumbwheel all the way in the other direction and measure the output voltage. Post the results from Steps 2, 4, 5, and 6.
On the left joystick the top switch is the horn and I found a broken wire for the bottom switch you think this could be my problem? I need to get a replacement pin for the connector
If you can post some photos of the area around the broken wire I can try to come up with some ideas. TBH I don’t think that a problem on the LH joystick could cause AUX issues but either way it needs to be fixed.
2 I have 8v. 4 I have 2.8v.5 I have 1.1v. 6 have 4.4v
From the voltage readings you obtained it appears as though your thumbwheel roller switch is working just fine. Next step is to get under the floor to the Interlock ECM, marked "B" on the illustration below. You need to backprobe wires P997-BR and P996-GN. You will find them on Pins 52 and 53 of the ECM connector. Then repeat Steps 4, 5, and 6 with the thumbwheel. You should get the same voltage readings as above but we need to confirm.
Same readings
OK, so that means the correct signals are reaching the AUX Hydraulic ECM from the thumbwheel switch. Now to look at the output voltages to the AUX solenoids A1 & A2. With the key OFF, unplug the 70-pin connector A-C5 from the AUX ECM. Locate the following wires: - P978-GN (A1 solenoid power) on Pin 40. L998-OR (common solenoid return) on Pin 42. P979-YL (A2 solenoid power) on Pin 58. On the main implement control valve locate the A1 and A2 solenoids using the illustration in Post #21 at the top of this page. 1. Apply 12v between Pin 40 and Pin 42 of the connector. Listen for a click in the AUX A1 solenoid. 2. Apply 12v between Pin 58 and Pin 42 of the connector. Listen for a click in the AUX A2 solenoid.
So at the solenoids I have one wire that has 12v with the key on and the other wire shoes 3v, the only way the solenoid will click is if I put ground to the wire that has 3v going to the solenoid
I think you misunderstood. I was asking you to unplug the big connector and apply 12v from the battery to one pin while you connect the second pin to machine frame ground. This tests the solenoid and its wiring external to the AUX Hydraulic ECM. You have to do the test twice, one for each solenoid.
Already did that and both solenoids operate as they should
In that case the bad news is that the AUX Hydraulic ECM is the root cause of your problem. It will require repair or replacement.
Ok thanks for the help
Where should I get an ECU replacement?
Ask for suggestions I would say. Somewhere I have details of a company who supplies replacement ECMs because you will have a heart attack at Cat prices (I think $3k+). I have not dealt with the company personally but know of others who have.
Check your message inbox.
I bought mine on eBay they programmed it with my serial number of my machine. I was having the same problem. I paid $800 for it. Caterpillar wanted $6500 which is ridiculous. This is in October 1, 2025. I hooked it up and now my control switch when I took the solenoid out I move it up and the solenoid clicks but my issue now is I’m not getting flow into the coupler lines so I am stumped there. Everything else works when I move the thumbs control up one clicks and you see the valve closing. Is that valve supposed to stay open and when you roll that switch you see it closing meaning the valve clicks and you see it flush when you look at the bottom of the Selnoid I have been trying to find a diagram or somewhat knowledge of how this solenoid is supposed to work from what it looks like it is in an open position and when you energize it, it closes flush when you looking at it from the bottom, correct me if I am wrong I will hook up a pressure gauge to the auxiliary port. I have all the diagrams and I’ve been working on this for like a month now any help is needed