My hydraulic thumb on my excavator works when it wants to, or either opens or shuts all the way by itself. It's a roll switch. I've been told it might be a solenoid sticking.
It could just as easily be a problem with the switch. Try posting a Serial Number to aid in looking up technical infomation.
That would be the easiest solution, but , of course you cant by switch separate. You got to buy the joystick with it, $600.00. I need to which one & where the solenoid is located in order to test it.
To locate technical information such as an electrical schematic will require the machine S/N. There are 12 different versions of the 303.5E, it would be a big help knowing exactly which one of them you have.
My serial number's CAT3035EERKY04412
OK, so the procedure to test your AUX thumbwheel switch is as follows. You will require a multimeter that has the capability to measure Duty Cycle because the signal from the switch is of the PWM type: - 1. Locate the 6-pin connector below the joystick and open up the two parts of it. Check for green crusties on the pins/sockets of both connector halves and if you find any treat with electrical contact cleaner as necessary. Re-connect the two connector halves. 2. Turn the key switch to the ON position. Using probes into the back of the machine side of the connector, measure the voltage between Pins 1 (power) and 2 (ground). It should be 8.0+/-0.5 volts. 3. Measure the duty cycle (DC) signal output of the thumbwheel on Pin 3. It should be 50% DC with the switch in the centre, 10% DC with it rolled all the way in one direction and 90% DC with it rolled all the way in the other direction. The DC % numbers are approximate but shouldn't vary by more than 1-2% from the numbers given. I have shown the RH joystick in the illustration but the exact same test procedure works for the LH one as well. The Pin Numbers are marked on the back side of both halves of the harness connectors which will help with identification.
If you don't have a multimeter with Duty Cycle, you can always use the HZ setting and check with that.
Most multimeters I have come acroos with a Hz button if you press it twice the DMM will be in the duty cycle mode. Pulse Width Modulated signals are a constant voltage and frequency, only the width of the pulse varies. So a meter set to Hz ought to display the same value whatever the output of the switch is. In the case of this particular thumbwheel switch it is the difference in the width of the pulse that we are trying to measure. If it's working correctly it should display 50% duty cycle in the centre, 10% when rolled to one extreme, and 90% when rolled to the other.
Nige, I, personally; have a tried and true Fluke 179 MM. No duty cycle, but it has HZ on it. Maybe it's time I upgraded............but my MM has worked well for decades through winter blizzards and summer heat. I'll stick with what I know. Some people don't have the latest and greatest. I'm giving him or her a work around if their meter doesn't have Duty Cycle. I just went through dealing with a thumb wheel on a 259 skid steer not operating a solenoid. Turns out it was the ECM. BUT I was able to determine the thumb wheel was working with my Fluke 179 set to HZ............wasn't elegant, but it worked. Then again.........if they had ET on a laptop you could plug into it as well and watch the outputs from the ECM.
The difference here is that we want to verify that the thumbwheel output is consistently 10, 50 & 90% duty cycle. Knowing it "works" isn't good enough for what I'm trying to walk the OP through here. I can see what you are getting at but although the Hz function might give an indication it is not accurate enough for the purposes of this test.
Got it.........thank you for explaining and clarifying!! I always appreciate your explanations.