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Help 2000 JLG 450A Diesel 4x4 Platform level problem

Jim913

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May 25, 2020
Messages
17
Location
USA
Hello,

i am new to the site, and looking forward to helping others and hopefully receiving some help along the way. A bit concerning about the lack of responses as I searched for people with the same issue as I am having. I didn’t find anyone with the exact sane issue but definitely came across others with various platform level issues. Appears to be a problem area on these units.

So, here comes my issue and question. All functions seems to work on my machine including auto basket level, if the basket it fairly level when you begin operation. From the ground station you can operate all function including platform level up and down.
From the platform, you can press the basket override toggle down and basket will go down, but if you press basket toggle up, it won’t go up, but you can hear the engine lose about 75rpm almost as if you were hitting a hydraulic pressure relief. This indicates to me the “new” toggle switch is working. I swapped the electrical connector 180d on the basket override toggle and when you press toggle up, the basket goes down, and when you press toggle down, it acts just like it did originally before reversing the connector, so that once again confirms proper toggle switch operation.

So, what could be the issue? Are there separate 2-way solenoid valves for the basket level function both at the ground station and the platform? That redundancy could make sense I suppose in case you get stuck in the air and need someone to assist from the ground controls.

Hoping someone might be able to explain the system design / function and point me towards next trouble-shooting steps.
 

Jim913

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Joined
May 25, 2020
Messages
17
Location
USA
After more reading, it sounds like the bang bang dump valve is not activating, but ONLY on one switch in one position (platform level up at upper controls platform).
I am unsure what could cause this condition since ground and hots are normally grouped. I traced 25-1 & 26-1 wires from platform level switch down to the ground control box and checked continuity across the terminal strip inside the lower control box. Upper control wires appeared to be tied in above the lower control wires as one might expect.
It seems like a simple singular issue but I still do not know enough about these units to effectively troubleshoot. The upper platform level switch is new.
Can anyone verify if the hand sketch and photo of the platform level switch appears to be wired correctly including diode orientation?
 
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ScottP

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Nov 15, 2019
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30
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Jayess, MS
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Shop Forman/Lead Technician/Truck Driver
FIND THE PLATFORM LEVEL UP AND DOWN SOLENOID VALVES ON THE FUNCTION MANIFOLD AND FIRST YOU CAN SWAP THE MAGNETS AND SEE IF THE PROBLEM STAYS WITH THE "UP" FUNCTION OR MOVES TO THE "DOWN" FUNCTION. IF THE PROBLEM STAYS WITH "UP" YOU GOT A SPOOL VALVE ISSUE {ITS THE PART THE MAGNET GOES ON SCREWED INTO THE FUNCTION MANIFOLD} IF PROBLEM MOVES TO DOWN YOU MOST LIKELY HAVE A MAGNETIC COIL PROBLEM..THAT WHAT WE DO WITH THE GENIE LIFT ISSUES IM SURE JLG ARE KIND OF SIMILAR BUT I COULD BE WRONG FOR SURE LOL
 

Jim913

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Joined
May 25, 2020
Messages
17
Location
USA
@ScottP - I thought of that too. On the right side of the main (largest) valve block, there is a single solenoid for level up/down and on the left side there I see no down only a single level up. I don’t understand that unless the level down from platform is through another relief. I have my focus on that left side level up valve at the moment. Keep in mind that it functions fine from the ground so provided they use the same valves then that shouldn’t be the problem. Possibly the platform level up valve it that single function valve on the left.

@willie59 - Serial number etc. is in one of the photos (0300060871). I think its actually a 2001 production year.
 

Jim913

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May 25, 2020
Messages
17
Location
USA
7002DFE8-262B-4E43-AC32-FB8F0328F1DB.jpeg I believe diodes at the switch are good based on findings above. Still unsure if wiring or direction of diodes is correct.
I checked diodes both directions (+/-) with connector socket removed from switch using a Fluke meter.
 

Jim913

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Joined
May 25, 2020
Messages
17
Location
USA
I disconnected the level up solenoid on the left side of the main valve block beside lower controls station and result was that when actuating the platform level up and down from the ground station, both toggle up and down resulted in the basket going down.
When testing from the platform, the toggle down resulted in the platform going down and toggle up resulted in no movement and the same sound as before of an over pressure or stalling pump noise.
 

willie59

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Dec 21, 2008
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13,363
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Knoxville TN
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Service Manager
Have you tried swapping the connection of blu/blk wire and blk/blu wire at the ground control box? Then operate your basket tilt toggle at platform, see if it will now tilt up but not down. Of course the toggle will be backwards in operation, but it would tell us you have a bad wire in the boom cable.
 

Jim913

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Joined
May 25, 2020
Messages
17
Location
USA
I verified the wires were going to the correct terminals at ground control but I have not tried swapping those wires as suggested. I will do that tomorrow and report back. Thanks for the assistance.
 

Jim913

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May 25, 2020
Messages
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Location
USA
Well things went from bad to worse. I swapped the wires at 8 & 17 and all the sudden my foot switch is acting up. I swapped wires 3x and the foot switch was dead whenever wires were swapped. I even left the wir Upon swapping wires back each time the foot switch is acting intermittent. I can hear it click down below and foot light comes on when it decides to work. Sucks because the level up from platform I could live with but an intermittent foot switch is a major safety concern. I guess getting the foot switch 100% is my new priority.
There were times when the foot switch light would come on and I heard it click down at the main and as soon as I pushed a toggle it would shut off the foot switch operation.

I should note that all testing was performed on electric power and I only moved the basket left/right and up/down toggles so main boom wires were not moving.
 
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Jim913

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May 25, 2020
Messages
17
Location
USA
Update:

I let it sit for awhile and decided to fire up the engine this time and check function again.
This time the foot switch worked no problem with several cycles. I raised the boom and then actuated the platform up from the platform and it worked (1 time). After that it was back to not functioning. Key here might have been raising the boom but when it worked, I wasn’t moving the boom between up/down platform cycles so the problem doesn’t fully follow a shorted or broken wire.
What is the easiest way to test wires? Should I be looking for an open wire or short at certain terminals? Bad ground?

Should I run a separate wire from platform down to lower control circuit and if so where is easiest place to tap in and easiest way to tap in?
 

Jim913

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May 25, 2020
Messages
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Location
USA
Update to the update:

I ran a jumper wire from 25-1 pink wire (platform up) down to ground control terminal 8 and it’s working like a champ.
Still unsure how that ties into the foot switch issue from earlier today.

@willie59 - Thanks for pointing in the right direction. Is the only solution to order and pull a new cable through?

How hard is that to do?

Have you ever sourced the bulk cable outside JLG? It doesn’t look cheap.

Any other hints or tips would be much appreciated as I am sure there is a sequence and boom configuration or configurations to ease replacement of the control cables.
 
Last edited:

willie59

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Check and see if the boom cable has some spare wires that are not being used at the platform, JLG typically has a couple of spares up there. On the schematic looks like there should be an ORN/BRN and YEL/BRN for rear steer option that may be available. If so, use one for those wires to replace your faulty platform tilt wire.

Check for any damaged spots in the boom cables. If it all looks good visibly, the problem is typically a broken wire in boom articulating joints or in the power trak. Power trak is a common place for cable failure from telescope cycling in/out over the years, eventually the bending of the cable breaks the wires internally. For that reason I only use JLG cable, they've been building these machines for a long time and they've figured out what wire works best and give longest service. Wire/cable that's not suited for constant bending will fail quicker which isn't really saving you any money then. Second reason for using JLG cable is you get the proper color code wires (or number wires) to match your diagrams. I've had customers provide me with other cables, not JLG, where colors don't match, hey, it's your party, you're gonna have fun trying to use the diagrams in the future.
 

Jim913

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Joined
May 25, 2020
Messages
17
Location
USA
Good call on using spare wires which might buy a little time. I definitely have spares because mine doesn’t have a jib.

JLG doesn’t make the wire so there are miles of it at some wire manufacturer. I will do some digging before I splurge on the jlg p/n
The excess cable in the track is pretty stiff, so probably time to replace it and maybe others as well. These machines can get expensive to maintain!

if anyone has tips on installing wires / hydraulic hoses through these type booms, let me know. The platform extend hoses look especially difficult to access the fittings up in the boom and those are getting down to the steel at spots in the track section and the steel is rusty. No leaks yet though.
 

willie59

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You would be correct, JLG does not make the wire/cable, but they have a supplier make that wire/cable to their specifications from years of experience, they've learned what works and what doesn't. JLG goes through a gazillion miles of wire in a given year at that plant, any vendor will bend over backwards to provide what they ask for. I've been in that plant in McConnellsburg PA, it's one helluva operation, and quality product is all they build.
 
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