Heavy Equipment Forums Heavy Equipment Community

cat 257 interlock issue

tom n ยท 2023-10-30 11:20

i have a cat 257 (ser. # cmm 00925) the engine starts but seat and park lights stay flashing and the hydraulics will not unlock.

Replies5
  1. #1Tyler d4c2023-10-30 12:13

    Remove the floor plate under there the 2 ecms set. There are famous for rotting though good first check considering there's 2 light I hope it's not your trouble tho. Have you checked anything else so far

  2. #2tom n2023-10-30 12:16

    i have checked the bar and seat switches. they are ok.i dont think the engine will start if one of them is bad

  3. #3Nige2023-10-30 12:39

    Door switch if it has one.? If not, as Tyler said get the cab up and see what sort of condition the Interlock ECM connectors are in. It's unfortunate that these early-model machines cannot be diagnosed using the Monitor panel, it needs something like ET or similar.

  4. #4tom n2023-10-30 13:29

    i will check. where can i buy a electrical schematic for this machine

  5. #5Nige2023-10-30 13:32

    You don't have to buy one. Check your messages, one is on the way.