CAT 247B

[bubba327]

I have a cat 247b and my switch for my aux hydraulic on my joy stick doesn't work properly.

If I push the button in the up direction you can hear the machine "bog down" as in the switch is working. Once I push the switch in the down direction I get nothing. In other words if I have a grapple on the machine it will close it but not open it.

I took the joystick apart and wasn't able to see to much. Everything looked to be ok, no loose or bare wires, and everything was tight.

I'm not sure where to start looking or what to start looking for. Fuses, relays, etc. I've seen other people say they replaced the whole joy stick and had the same problem afterwards.

Thanks for the help!

 

[Steve Frazier]

Get the serial number handy, our resident Cat expert will need it to help you. Best thing to do is get a schematic so you can trace the circuit and determine where the problem is.

 

[bubba327]

 

[Nige]

An electrical schematic is on the way. Keep an eye on your message inbox.

First thing we need to establish is what the thumbwheel roller switch on the joystick is doing.
See the illustration below. Locate the 12-pin main harness connector directly under the RH joystick and identify Pins 1, 2, & 3.
You will need a multimeter and suitable cables to back-probe into electrical connectors.

1. Turn the key ON and measure the voltage between Pins 1 & 2. It should be 8.0 +/- 0.5v.
2. The key remains ON. Measure the voltage between Pins 2 & 3 with the thumbwheel roller switch in the centre position.
3. Repeat Step 2 but with the thumbwheel rolled fully forward.
4. Repeat Step 2 but with the thumbwheel rolled fully back.

Report your results.