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Cat 315BL

pbean · 2026-08-19 20:56

I have a 315BL the heater and AC control panel stopped working. I have power at the fuse and relay and I have 24 volts and a ground at one of the 2 connectors on the bottom of the control panel So thinking the control panel itself was bad I bought a new one from cat.it still doesn't work. I have a wiring diagram but I only see the one power coming in on the schematic. Also the schematic I believe is only showing one 21 pin connector at the control panel. I have a 20 and a 16 pin connector The 16 has no power. My serial number is 3aw01742

Replies15
  1. #1John C.2026-08-19 21:50

    Find a way to hook up power directly to the motor. It was pretty common in those days for the motors to fill with dust and get frozen up.

  2. #2Coaldust2026-08-20 00:03

    I believe the HVAC ECM supplies power to the control panel. Are you saying the control panel is completely dead? No lights? That system has its own trouble codes you can access with the control panel. It operates off a j1939 canbus. Rather innovative for that time period. If the control panel is completely dead, I would look at the ECM. Cat has a book that covers that system. Not the service manual. Supplement SENR6079 From May 1993. Twenty bucks on the EBay.

  3. #3Nige2026-08-20 04:52

    Do you have an OEM schematic.? Cat Publication reference RENR1132-01.?

  4. #4pbean2026-08-20 06:19

    That's correct the lights on the panel won't come on.completley dead.thanks for the info

  5. #5pbean2026-08-20 06:22

    The wiring diagram I have is in the service manual.RENR1132 Doesn't have a -01 ?

  6. #6Nige2026-08-20 06:34

    You have the original version, -00 if you will. -01 is an update. You’re welcome to a copy if you want one.

  7. #7pbean2026-08-20 07:13

    That would be awesome! I looked on eBay only one available is for a 320 and up Thanks

  8. #8Nige2026-08-20 08:15

    Check your message inbox.

  9. #9Coaldust2026-08-20 09:04

    The HVAC system on your machine is the same. Cat also has a nice HVAC training booklet available for 300 series that could be helpful. It’s difficult to source because it’s part of the ThinkBig curriculum. https://www.scribd.com/document/821023725/UNIT5L1S

  10. #10Coaldust2026-08-20 09:08

    Then, I would think the control panel has lost communication with the ECM. Might just be a corroded connection. Probably need to remove the seat to get decent access to everything.

  11. #11pbean2026-08-20 21:05

    Thanks for your help! It was the inline glass fuse behind the seat. Pulled the seat out. It needed cleaning anyways

  12. #12Coaldust2026-08-20 21:23

    Glad that’s all it was. Thanks for the update. What did that controller cost? Someone must have messed around at one point, because Cat never hid a fuse behind the seat.

  13. #13pbean2026-08-20 21:35

    Looked like a factory deal with the inline fuses. Controler was $375. My old one was becoming delaminated on the buttons anyhow. Was a lil nervous about buying an aftermarket one off Amazon. Looked at my 312C controler to see if it was the same and it's a different part number but looks the same. Cat wanted $1000 for that!

  14. #14Universal Parts2026-08-21 05:56

    It's probably an aftermarket part. You can't buy an original part for 375 USD; if it's an aftermarket part, that price is too high.

  15. #15pbean2026-08-21 06:58

    All the parts right now are too high !