Just bought a bobcat 325**G and added a thumb, only to find that nothing happens when the switch is activated on the joystick. The mount on the machine looks like there never was a cylinder mounted. The auxiliary indicator light on the panel lights when the switch is pressed. Is there anything else that needs to be done for the first time use of the auxiliary hydraulic circuit or anything I should check? Thanks for any help.
Good day To operate the thumb using the buttons on the lever requires that the machine has two proportional valves controlling the auxiliary spool. I suggest follow the lines from the thumb, then the control lines from that valve. That way you can find the prop. valves, if you have them. Kind regards Uffex
Thank you for the information. What voltage should be present at the valve when it is activated? Thanks again dusky
Good day dusky The voltage is tricky as the signal is pulse width modulation, sorry you normally need an oscilloscope to measure. Much easier to measure the output pressure of the valve with a gauge, that is at each end of the spool caps. Kind regards Uffex
OK thanks for the information. I will see what I need today to test them. Best regards, Dusky
The solenoids on Bobcat stuff is 12v. When you press the switch do you hear a difference in the engine and do you see either of the lines on the stick jump? Does it sound like the hydraulics are dead heading?
This is from a 331, 334 model but they are very similar. As you can see the Aux solenoids are controlled by the machine ECM. Check for 12v at the solenoids when you press the switch. If your not getting 12v double check your continuity of the wire using the two connector ends. If the wire checks out as good then you might have a ECM problem. The wire from the joystick to the ECM and the switch should be fine because you said it lights up the dash when you press the switch. If you don't have 12v at the solenoids you can manually power them up to check for operation. Use a Power Probe like this https://shop.powerprobe.com/na/en/product-list/content/PP3 They are really handy to have when diagnosing electrical problems.
There is no change at all on anything when I move the switch. I will check it for 12 volts today. Is the 12v coming straight from the ecm or is there an external relay? Thanks, Dusky
If that 331 is built like my 337, those connectors that connect to the solenoids dont seal out moisture well. Plus there are several connectors throughout the machine that arent waterproof at all. Had corrosion issues in a few of my mine.
Thanks to all the help, I got it working. I checked the voltage with my voltmeter, got 9.5 volts on both solenoids. I pulled the valves out and both were stuck. I sprayed them with solvent and tapped them on a lead block. Kept putting the coils back on them, checking and tapping until both of them were free. The thumb works now. The speed looks correct but the pressure needs to be adjusted down. If anyone could get me started in the right direction for that I would greatly appreciate it. I will do a search also. Thanks again for the help. This is a great site. Best regards, Dusky