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Cat 277B bucket hydraulic problem

LarryW ยท 2013-03-06 15:13

I have a Cat 277B skidsteer. When i turn on the front lights, it disables the bucket hydraulics on the right stick. Lights off and everything works fine. I have lifted the cab and searched for any worn or damaged wiring. Also have replaced the front light switch and the hydraulic cutoff/overide switch. Any help would be greatly appreciated. Thanks!

Replies13
  1. #1ctheddy2013-03-06 22:23

    Headlight wiring crossed with door safety switch maybe. I would check behind the inside panel, upper left behind park brake/ left headlight. Do the lights work when they are turned on or does it just cancel bucket hydraulics. Will it drive while the bucket hyd are being interrupted or does it disengage all controls? I say the door safety swicth because I think that just cancels the bucket hydraulic, not the drive motors...

  2. #2LarryW2013-03-06 22:54

    Lights work when the switch is turned on and it drives also. It only cuts out the bucket controls

  3. #3LarryW2013-03-06 22:57

    Bucket controls work fine with the front lights off. Only cuts out when front lights are turned on.

  4. #4Delmer2013-03-06 23:11

    History? is this out of the blue? or did you get the machine this way?

  5. #5LarryW2013-03-07 12:12

    Just started it recently. Been a while since it was used at night, that's when I discovered the problem. Also the door has been removed and the switch jumpered

  6. #6mikebramel2013-03-07 16:16

    Check the ground for the lights and the light relay they may share common ground and feedback from the high amperage lighting is not allowing the coil to be energized with the right polarity

  7. #7LarryW2013-03-07 20:11

    How would I fix that if it were the case? All of the grounds run down to the grounding bar under the cab

  8. #8LarryW2013-03-07 20:15

    When I run the rear lights it doesn't kick out the bucket hydraulics

  9. #9mikebramel2013-03-07 20:16

    So if just the front lights are causing a problem disconnect them or remove the bulbs and turn them on. Same problem? Positive side problem. No problem? Probably ground side

  10. #10LarryW2013-03-07 20:37

    Disconnected lights and same problem when front lights turned on, no bucket controls

  11. #11mikebramel2013-03-08 10:07

    Trace between the lights and the switch

  12. #12LarryW2013-03-08 11:51

    Traced all wiring on the harness inside the cab and found no issues.

  13. #13LarryW2013-04-15 20:24

    Here is an update. Found the problem. It was the jumper in the door switch. When I put the door on and plugged it in everything works!