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JLG 450A Yr 2000 Ford Dual Fuel Gas/Propane-Platform controls DO NOT work, Ground Control Works Fine

pk9909

Member
Joined
Feb 27, 2021
Messages
8
Location
KY
2000 JLG 450A Dual Fuel Gas/Propane, Starts and runs great on either fuel. Ground controls work fine. You can start it from the platform but when you step on the dead man's pedal nothing works. Just no Power to any controls on the platform and it doesn't rev up when pressing the pedal. You can then shut it down and restart it and switch fuels from the platform. Just can't operate the platform or steer the wheels or make it move. The Voltage on the dead man's pedal Norm Open and Norm Closed switches voltage descends rapidly from 35-13-5 to OL and then starts over. It will read zero if the pedal is depressed like normal. It does this on the ground/platform control selector too at the ground control box. Maybe this Voltage is normal but I assumed it would be a constant voltage. Not sure if that's the problem. The same descending voltage reading is inside the platform control box where the dead man's pedal attaches to the Platform distribution (So no break in wire from pedal to platform). When I check the voltage of the Ground/Platform Selector switch in the ground control box it has this fluctuating voltage also but like I said earlier...the ground controls work so I didn't think this was the problem. Any help would be greatly appreciated.
 

Txhayseed

Senior Member
Joined
Dec 23, 2019
Messages
610
Location
Texas
Do you have a analyzer ? Sounds like your foot switch is not working. If you can start the unit from the platform your getting key power to the platform via the estop. Next step would be the foot switch to tell the platform control unit the connection was made and its ok to go ahead and perform a function. You can use a jumper wire to bypass the foot switch with the cover off it once you have started the unit. If the unit operates then you know its the switch inside the pedal box. If not you need to follow the three wires up. 2 go to the platform control model 1 goes the deutz hd connection under the control box to main boom cable. Thats where i would start. If you got the analyzer you can check all the above mentioned with the hand held.
 

pk9909

Member
Joined
Feb 27, 2021
Messages
8
Location
KY
Thanks for the response Txhayseed. The foot switch depresses and you hear the two switches inside click. It is a Hercules dead man pedal btw. When I have a voltage meter on the common and Norm Open there is voltage and when you presses the pedal the voltage goes away and is transferred to the Norm Closed switch. Both switches operate this same way. That seems normal to me. If this is the case could it still be the foot switch for some reason. It does seem the most likely problem but it also seems to be functioning normally. here is a pict of the foot switch. Unfortuantely I don't have an analyzer.
 

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pk9909

Member
Joined
Feb 27, 2021
Messages
8
Location
KY
Thanks for the response Txhayseed. The foot switch depresses and you hear the two switches inside click. It is a Hercules dead man pedal btw. When I have a voltage meter on the common and Norm Open there is voltage and when you presses the pedal the voltage goes away and is transferred to the Norm Closed switch. Both switches operate this same way. That seems normal to me. If this is the case could it still be the foot switch for some reason. It does seem the most likely problem but it also seems to be functioning normally. here is a pict of the foot switch. Unfortuantely I don't have an analyzer.

I'd like to add that I don't think my machine has an analyzer. I looked under the console and in the ground control box and I can't find a port.
 

pk9909

Member
Joined
Feb 27, 2021
Messages
8
Location
KY
I just did some more testing...checked continuity on both microswitches in the pedal...both switches have continuity between common and Norm Open and Norm Closed posts when the pedal is pressed and released so they seem to be performing normal. Also ...the lift won't start if the pedal is pressed so that is normal too. If you look at the picture I posted of the inside of the foot pedal, The black and orange single wire are the COMMON posts. I tested the continuity of both of these COMMON posts and a grounding screw in the pedal. The orange wire DOESN"T have continuity and the Black wire DOES have continuity when grounded. That seems strange to me since I though both of the COMMON terminals were power to the switches. Hope this tells someone something. Maybe this is normal.
 

Txhayseed

Senior Member
Joined
Dec 23, 2019
Messages
610
Location
Texas
Yes thats normal. The machine should not start with the foot pedal depressed. With the machine running hold the foot pedal down with out doing anything else. After about 15 seconds you should see the fault code indicator light up on your panel. If it does not cause the fault code indicator to come on after about 15 to 20 seconds its not seeing the foot switch input and your problem is with one of the switches or the wiring from the foot switch to the control box..do know the serial number to the machine ? The unit has to see that the foot switch is open to start and closed to perform any secondary function like lift or drive etc.
 

pk9909

Member
Joined
Feb 27, 2021
Messages
8
Location
KY
I feel like there is some voltage problem. The voltage dances from 35 to 14 to 5 to OL over 1-2 seconds when I hold the volt meter on one of the posts that in your diagram says 12v. Surely this isn't normal. Shouldn't it just be a solid 12v?
 

Txhayseed

Senior Member
Joined
Dec 23, 2019
Messages
610
Location
Texas
35 volts ???? That is not even possible. Is your meter set on millivolts ? Ol would indicate that the reading is out of range of the meter. Its a 12 volt system. Not sure what your using to get these readings. If you believe its a voltage issue check estop voltage. The estop feeds the system. It goes there first. You can then follow the foot switch cable up and test your voltages inside the control box. Again your readings are not jiving. I would double check your meter.
 

pk9909

Member
Joined
Feb 27, 2021
Messages
8
Location
KY
IMG_8862.PNG Meter is right. Nice Klien. I can put it in a 120v plug and get 120v, I can put it on the battery and get a solid 12v. Inside the platform control box and the ground control switch it gets the same dancing readings of 35 descending to OL. It does this descending pattern over and over. Here are the images of the voltage drop. These are screen shots from a 1-2 second video.
 

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pk9909

Member
Joined
Feb 27, 2021
Messages
8
Location
KY
OK...so I hate to admit this but the meter was flipping around because it was still on AC instead of DC....I'm an idiot. anyway....12v running correctly through foot switches. Looks like there is no power going to one of the wires on the right 7 sec delay relay that SHOULD have power. I was able to jump a wire from one 12 V spot to this Terminal and energize it and I'm back in business. I'll unravel the squirrel nest of wire in the basket controls another day and trace it back. Thanks for your input txhayseed.
 
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