Hey guys first time to this site. A wealth of information. I have a 1999 jlg 40h. When I switch it to platform control the voltage drops to 11v from 13.5 and about 20 seconds later the machine shuts off. My guess is something is shorting on the platform side, getting hot, and opening a solenoid. Or something along those lines. I haven't worked on a machine like this before. Any help would be greatly appreciated. Thanks Josh
Welcome to HEF Perzeej. :drinkup Might take a while to sort this one out here. Where are you getting this voltage reading? What engine does the machine have?
Hey willie59. I was watching the voltmeter on the machine. It has a 3 cyl diesel if that helps. The wire that connects the I terminal on the backside of the master to the platform/ground switch is definitely hotter than it should be but not melting. Thanks for your help
3 cylinder diesel should be a Deutz F3L912. Ok, that red wire that goes from I terminal on master power switch to the terminal on the upper/lower select switch is the main ignition power wire. You stated earlier that you can see a good 13 volt on the volt meter when lower controls are selected with that switch, but when you flip the select switch to upper (platform) controls you can see the voltage drop to 11 volt on the volt meter and that red wire gets hot. First, with platform controls selected, pull the orange 12 gauge wire loose from the select switch, this should make the volt meter bounce back up. If it does, reconnect orange wire and pull blue wire loose from select switch, see if it still pulls volt meter down. If it does, you've isolated the problem to the platform. If this is the result you're getting, the orange wire sends power to the platform and connects to terminal 34 in the platform control box. First try disconnecting orange wire from terminal 34, see if volt meter changes. If it stays at 11 volts, problem with cable going up boom. If it jumps up, keep going. Reconnect the orange wire to terminal 34 and disconnect any other connections to terminal 34. You've got to isolate which wire/circuit is putting a load on the ignition circuit when platform controls is selected.
Hope you had a good weekend willie59. I started the machine, pulled the Orange wire and flipped to platform. It died immediately. Did the same thing with the blue wire removed. With the lift cold I can run it in platform for about 5 min. Long enough to get it moved into the shop. It shows 11 V, but doesn't die. When it's warm it dies as soon as I put in platform. Not sure if this is relative. Relay related?
Perzeej, I'm not concerned with the engine at this point, yes, it will die when you pull those wires, that's the main ignition wires, what I'm looking for is what the voltmeter is doing, we're trying to narrow down and find an electrical short because it sounds like that's what you have going on there. The most likely culprit is a problem with the cable going up the boom, but we have to narrow down which wire is causing the problem because there's a pile of wires going up that boom. Forget about the engine, just turn on the ignition and follow the method I posted above and let me know the result of each step. Since I'm not at the machine this is the only way I can narrow down where the source of the problem is.
10 4. With the engine off it shows 12v in ground. Switched to platform it goes to 0. Removing Orange wire while in platform creates sparks. Removing blue wire while in platform does nothing, still 0. I can hear the same solenoid clicking when I turn the key on or when I flip the switch to platform.
Willie59, if you're near NW indiana I will gladly pay you to work on this lift. I can't find anyone near who knows much about these. Thank you for the help.
Nope, planted firmly in the foothills of East Tennessee. Ok, ignition on, engine not running, ground selected, volt meter reads 12V. Ignition on, engine not running, select platform, volt meter drops to 0. Pull orange wire at select switch and you get a visible electrical arc. Reconnect orange wire, pull blue wire at select switch and you don't get a similar arc, volt meter remains at 0. Is that about right? If so, there's a 12 gauge / 4 conductor cable that goes from lower control box, goes up the boom, and terminates at the platform box, black, red, blue, and orange. These 4 wires from that cable connect to terminals 31 32 33 and 34 respectively at the terminal strip inside the platform control box. Find where the orange wire from that cable connects to terminal 34 and disconnect it from the terminal strip. Now don't confuse the cable that goes to the foot switch, it's the same type of cable with same color wires, make sure you disconnect the orange wire from the cable that goes to the ground control box. Once you do that, orange wire disconnected at platform, turn on ignition at ground controls, select platform, see if you still get that electrical arc when you pull orange wire loose from select switch. BTW, when searching for a short circuit like this it helps to use a amp clamp meter. A volt meter will do, you can still see a current drain on a volt meter because the drain will make the meter drop, but a amp clamp meter will tell you how much current is going through the wire.
We fixed it. After tracing the Orange wire and checking all connections it led me to the foot pedal. Right switch was closed when it should have been open. Thanks willie59 for your help
Yep, that would do it, the black wire on that switch goes to ground (earth). The switch is Normally Open, so if it were tripped, it would send the ignition circuit on the orange wire at the other switch straight to ground.