I am assisting a friend with some electrical troubleshooting on his 2 322BLs. Both are mid to late 1990s (1997, i think) and are exhibiting the same issue lately. The displays stay blank after starting until they have been running for about 20 minutes, when they start working, although he says they are intermittent still. I have confirmed good power and functionality of the displays but, without manuals or schematics, I am having a hard time isolating the cause. One is out on the job and the other is accessible while we find the fix. With both acting up at about the same usage time, i assume this is a fairly common issue. I did access the disconnects under the trim in the cab and they are pristine. The serial number of the unit I have access to is 2ES00290. Thanks to all!
Here only replacing the displays with new ones will help. To make sure that the display is faulty, you need to find a known good one and install it for testing. The faulty display starts working normally when it warms up. And try to remove the wires from sensor #106-0178 which is on the main pump. One wire of the sensor is connected to the display.
While I had both excavators together, I plugged the 'faulty' display into the good machine and it worked fine, on a cold start up. There is also is no response from the engine throttle knob (a 1/2 turn potentiometer on the right hand console). Not sure if that is related at all. I have power on the red and black wires on the display, but am not sure what the pink, brown and yellow wires attached are for. Thank you, I will look into the main pump sensor connection.
Do you need some electrical schematics.? The 2nd machine may require a different one to the 2ES-prefix machine. Needs a Serial number to confirm.
It seems like they are both acting the same way, according to the operator. The serial number above is for the machine he isn't currently using and the one im troubleshooting at the moment. Schematics would be extremely helpful. Hopefully it's a faulty relay and I can pin-point it on both units l, once ib know what I'm looking at. Greatly appreciate the assistance! Thank you all
Check your message inbox for an electrical schematic.
Thank you, Nige! that was most helpful in verifying good connections and the Pump Pressure Discharge Sensor signal as NOT being the cause. These are my findings from today: I'm assuming the RS485 on the Monitor (F-1 on the schematic, K911 and K912) are the data +/- for display on the monitor. Am I correct? And if I am correct, that signal comes from the Engine/ Pump Control (through connector 16 and 44) and would not affect the display coming on, right? I wanted to check the Pump Pressure Discharge Sensor because it (the +B or V Sensor) has a signal that goes directly to both the Monitor and the Engine/ Pump Controller, though I thought it was just for data to be displayed? I am looking at 2 potential issues, I think... One being I am not sure where the Engine/ Pump Controller is located nor what it is. Is it a smallish box with circuit cards, or something different? Page 1 makes it look like it is in the cab (makes sense) on the right. The right hand arm area has a throttle control potentiometer, which is also not working, and a few switches. Might the lack of throttle control be related? I'm wondering if the Engine/ Pump control is failing on both machines. Behind the seat looks like an amplifier and the air blower equipment, nothing of which had all the wires pinned into it. The second issue, maybe, is that the red (wire 103) and black (wire 201) have battery power, 24 Vdc on them with the main switch (behind the cab) on, then stays around 28 Vdc with the engine running. That just looks like a good alternator to me. The monitor on the sister excavator in the field went from taking around 45 minutes of the engine running, in 85 degree weather, last week, to 2 1/4 to 3 hours of operation to come on in 65 degree weather this week. The unit I'm working on did the same last year before it stopped coming on. I am wondering if it may be a manufacturing issue within the monitors? Thank you all, especially Nige, so far. If anyone else has had this problem with their CAT 322BL, I would love your input!
Here's all there is regarding the Eng/Pump Control mounting & location. I also found the SysOp and T&A documents for it.
Thank you yet again, Nige! That information should come in most useful, for sure! For anyone else experiencing monitor AND throttle issues, I found this video on Yoputube: It was helpful to me in eliminating a few more things. That being said, there is still an issue with the monitor(s) on both machines not coming on, no initial beep, no display at all for the first hour or two of operation. They then go on and off randomly throughout the rest of the day. I've traced all input wires to the monitor, even as far as the "cab lamp/ light" 615-yl-18 and all have been confirmed good wires (no shorts, open to ground). Has anyone seen this issue before?
Thank you, Nige, for all the help! I've learned a lot about these excavators through this. Found out the issue, on one machine anyway, was the BU K997 pin at the back of the monitor. It was not making contact properly. After re-pinning the wire, it works just fine.