Hi,
Your truck E14-02 S/N H2X335L01555 was built in the year 2000.
I have seen you have checked almost everything.
You said " If we plug into the lift circuit, we get fault codes 35, 36, 37 & 38 which all relate to the levers "
=> I assume that you have seen these codes via Linde Truck Doctor, haven't you?
Yes, these codes are all related to the signals of hydraulic levers.
But I see that you have already done everything which we need to check.
As my experience, you should try to check some additional steps as below:
1) Try to check the output of the DC/DC Converter to see if it is correct 24VDC or less...if it is less than 23.7VD e.g. =23.6 or 23.5VDC => you should try to change another one for testing. I do agree that you have got a 14.3 VDC power supply for the joysticks. Yes, it is correct, but sometimes if the 24V power supply for the LLC is too low it also makes the LCC lift controller crazy. Therefore, let check it out.
2) Basing on your measuring results, it seems to be all the wiring are OK but in some cases are not since I used to face with some case likely this before: power supply is OK, the signal value is OK, Continuity check is OK but the error codes are still there.
=> You should try to change new wirings for the power supply and signal for the joystick => only need to change some piece of wire from LLC controller tp 2X3:1 & 2X3:6 as well as from LLC pins 2X1:10 to 2X3:2 and from LLC Pin No. 2X1:11 - 2X3:4. This is because the wirings are out of the lifetime or oxidized internally and have very bad signal conductivity.
3) Lastly, you should borrow another LLC to replace for checking or send your LLC to the agent or your friend ask them to check if it is still in function.