Hitachi 120-2, not the standard problem

[wilko]

When I turn the machine off the battery warning light comes on and the various other indicator lights (travel speed, mode, throttle setting) stay lit. Disconnecting the battery "resets" the system, when I reconnect the battery all the indicator lights are off. The machine restarts fine, shuts off fine, but the indicator lights stay on again.

To clarify, engine shuts down when I turn off the key, but charge light comes on and indicators stay lit.

Ideas?

edit: Unplugged the connector on back of alternator to see if alternator was problem, now disconnecting and reconnecting the battery doesn't "reset" the system.

 

[Bls repair]

Have you checked out the key switch to see if it is operating properly?

 

[Ronsii]

Like BLS says check the key switch first if it isn't that then move to check the relays under the main disconnect relay... and check that one too... as it may be sticking but one of the relays under it control it and that get's the signal from ... I think a relay in the bank below the computer as the stay alive relay... going from memory here... sounds like one of them is leaving the controlling voltage up or maybe a hot wire is shorting to another wire that should be goid dead instantly as the key is switched off...

 

[wilko]

Haven't pulled it apart yet to get at the ignition switch. First thing I did was jiggle the key back and forth because sometimes you get lucky. I'll start there. If I have to chase relays, .........shudder.

 

[joeblow]

There is a load dump relay in the system to keep a circuit closed for the alternator when the key switch is turned off and the engine is still rotating .Since your machine is a dash 2 (grey market) it might be labled in Japanese.Start by switching relays one for the other and see if it solves the problem.

 

[joeblow]

Also try pulling the "monitor" fuse and see if that resets the lights.

 

[LukeS]

i am having this same problem with my 490E if i pull the relay for the load dump the lights on dash turn off but as soon as i turn to start, no start and lights stay on until i pull ground on battery or pull load dump fuse. if i turn key to start really fast it will bump starter once and still no start. i can start from key if i unplug the monitor controller. if i plug that back in the only way to start is to bump the starter and she will fine all day, but when i shut off i have to pull the ground to shut off the lights on dash, also i have to keep the oil pressure unplugged or the buzzer will just stay on. i already did new key switch, oil pressure switch, battery and starter relay, checked all grounds, unplugged all senors on the motor, and unplugged all relays and tryed them with a new relay.

im ready to just put a bush button to the starter and a battery shut off in the cab!!!!!!!

 

[excavator]

Check your alternator by unplugging the 2 wire plug in on the top. Most often I have found a bad diode in the alternator causes this problem.

 

[mg2361]

Welcome to HEF Luke!

More specifically, when you shut down and the lights and buzzer are still on, run a jumper from the blue/yellow wire at the alternator to a good ground. Do the lights go out and the buzzer stop? Will it restart after doing that? If so you have a bad voltage regulator in the alternator.

 

[excavator]

Welcome to HEF Luke!

More specifically, when you shut down and the lights and buzzer are still on, run a jumper from the blue/yellow wire at the alternator to a good ground. Do the lights go out and the buzzer stop? Will it restart after doing that? If so you have a bad voltage regulator in the alternator.

Thanks for clarifying that mg2361. If I remember right I have had a bad rectifier diode bridge do that also.

 

[LukeS]

I will try that in the morning when I'm back at the shop but even with the alternator unplugged and I shut it down the lights will still stay on in the buzzer. If I disconnect the little white voltage regulator that is inside the cab it will shut everything down. And with the key off the red with black stripe wire remains hot

 

[LukeS]

We had an alternator problem with this machine a few months ago and I bought one from Napa and I put it on in the ignition lights and buzzer stayed on when the key was off I took the alternator out brought it to my alternator rebuild guy and he took the back of my old alternator and put it on the new alternator. It was fine for months but we noticed and have had an issue with the machine with the low oil indicator light and buzzer staying on for long periods of time. And when the machine stopped working one of our guys turn the key off the buzzer was still on and he left I went back to the job about an hour later the buzzer was still on and that's when it wouldn't start again

 

[joeblow]

Check your alternator by unplugging the 2 wire plug in on the top. Most often I have found a bad diode in the alternator causes this problem.

Check your alternator by unplugging the 2 wire plug in on the top. Most often I have found a bad diode in the alternator causes this problem.

We had the same problem with the 892E and it was the alternator.A shorted diode on the Delco alt would send a signal to the brain box that the machine was still running when it was not and the oil pressure switch would set off the monitor buzzer.The only way to get it started was to pull the monitor fuse.

 

[LukeS]

I had that issue a few months ago. But now even with the two wires unplugged from the alternator and the only wires connected to the alternator is the ground and hot wire just wanted to buzzer and the lights stay on even with the key off

 

[joeblow]

Do you have a schematic for the charging system?Try disconnecting the battery wire as well.

 

[LukeS]

I don't have a schematic on the charging system I just have a technical repair book and a parts book not much!! Technical repair book really doesn't break down the wiring diagram. But when I pulled apart the wiring looking for phrase I noticed that the big white positive wire that comes off the alternator goes down and right around the oil pan it tees off and one goes towards the relay near the batteries and the other one goes up into the cab

 

[joeblow]

I will send you a schematic and a theory of operation.Its near impossible to diagnose an electrical problem on these machines without it.now if I can just figure out how to use my scanner...

 

[LukeS]

Would I be able to find the electrical schematics online

 

[joeblow]

I hope this will clarify things for you as what does what to what.

 

[LukeS]

thank you yes looking at the wiring schematic does help!!! What's the name on that book I want to order one