I just bought a nice 1995 312 Cat excavator. SN: 6BL00906 It has 4600 hours and was well maintained by the original owner. The issue I have is the A/C box that is mounted to the floor behind the operators seat. I vacuumed the interior of the box to clean it out and found linkage parts that control the louvers. None of the lovers work via the servo motors. I called Cat for the hell of it and it's $3100 for the box and $700 for the control panel. (upper half of the control panel isn't working) Has anyone swapped the stock unit for aftermarket like Red Dot? Thanks for any info
When you say "upper panel doesn't work, in my experience, any one jammed servo (rock or failure), and the mode select simply defaults, but, I cannot recall what that panel looks like. The newer units (and possibly that one) cycle all actuators at startup. Whichever doesn't move at all is suspect, and whichever stutters is possibly jammed with debris. Can you post a pic of the hvac control?
Good info! I'll check for cycling and try to get a picture.
Long story made short.... heyMccall gave me the little nugget of info I needed. I ended up removing all servo motors and cutting the shafts off that go to the louvers. I then reinstalled the servo motors. Now when you turn the key on, everything cycles and the keypad no longer locks out. I set it up so the heat now only comes out at my feet which is fine with me.
Why? Really, why cut all the shafts? Hang each servo loose and retry. Then, physically turn each shaft, inspecting for bind. And, worst case scenario would be to leave the actuators hang loose. But, cut the shafts?
I had thought of that but ultimately didn’t want them dangling and upon further inspection the plastic bushings were shot. Mice had eaten the rubber off the louver doors etc.. so I made the decision to cut the shafts. I set it so the door to allow heat to your feet is gone.