Hoping for some insight. I have been working on a 1999 JLG 450A for some time now. the unit originally lost the main rotate function and slowly lost the tower boom, basket rotate and basket tilt. The main boom and telescopic functions still work as well as drive and steer. I have ruled out the auxillary pump, have gone through all valves and solenoids on the main valve block, and replaced what I found to be bad. also verified fluid is returning to the tank. I did find that there is a constant flow of fluid through the return that does not increase or decrease in pressure when attempting any of the functions that are not working. I have verified that the pump is supplying proper pressure to both the G1 and G2 ports on the main valve block. I have been back and forth with JLG tech support as well and to no avail I still cannot seem to locate the problem. any and all help would be greatly appreciated.
Are the solinoids getting power when a function is activated. Does it not work it from both ground controls and the basket
A lot more information needed but do functions work from ground controls, that's the first question I ask. Second is machine serial number and what engine.
Yes solenoids are receiving power, and functions don’t work regardless of attempt from basket or ground controls.
It has the dual fuel ford and serial is 0300043963
Ok, looking at the schematics for that serial number range, that model was prior to JLG using a computer in the upper and lower to control everything by CAN Bus, everything on your machine is pretty much old school switches, relays, and solenoid coils. And since you have the same problems from the lower controls, well, that's where you always want to start. Don't even bother with the upper controls just yet, get it working from the lower controls and the upper may fall in line. But here's the thing, from the issues (multiple) that you're describing, there's no way we're going to be able to pinpoint where your problem is. What you're going to have to do is study your electrical schematic, again, only follow paths for lower controls, get your test light out and start testing circuits following that diagram. And for sure check all those cables connected to the lower control box for rodent damage, I've seen that many times.
Sorry for the delay, but makes sense I will spend some time going back through the lower harness and I will let you k ow what I come up with. Thanks for your feedback