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catmastertech, Technician
Category: Construction and Road Equipment
Satisfied Customers: 2334
Experience:  Field service technician for CAT 19 years.
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312B the hydraulic safety will click on while operating, i

Customer Question

312B the hydraulic safety will click on while operating, i have ruled out the micro switch, and have located the small black relay in elec. panel. that is clicking, not sure what or where to check next.
Submitted: 1 year ago.
Category: Construction and Road Equipment
Expert:  catmastertech replied 1 year ago.


Please post the full machine serial number so I can research the correct information about this machine.

Are you saying the lock will click when you move the safety lever? (This is the correct function)

Or are you saying it is turning off and the machine is stopping?

Is the charging system working?

Are your batteries testing good?

Have you checked for voltage at the lockout solenoid?

Please provide more details about what is happening to the machine?

Customer: replied 1 year ago.
Thanks for reply , what should I look for first . I own a starter & Alternator rebuilding shop. I am sure alt is 28+ . Batts at 90+% cranking amps. I need to know what the path from micro switch to pilot release is .. At least I think 😁
Expert:  catmastertech replied 1 year ago.

At switch,

Red #150 wire is power from hydraulic lock fuse.
Green #151 wire goes to hydraulic lock relay.
Red #154 wire goes to neutral start relay.

From hydraulic lock relay,

Green #A588 wire goes to hydraulic lock solenoid.
Power to relay is from the same fuse and wire. (Red #150)

Black #200 wires are grounds.

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