Hitachi ex120-5 won’t turn off with key

[maineplower]

I have a ex120-5 that I bought with the throttle control missing. I put a new motor and cable on both Deere. I’ve set the idle rpm’s with the computer and done the learning procedure. I tried a different key switch. Still it won’t turn off with the key. Any ideas??

 

[mg2361]

I think that machine is the same as a Deere 120. If so, sounds like the V2 alternator shut down relay isolation diode is shorted. The diodes are behind the seat, below the fuse box. To identify the diode in question, it should have a red/white and red/black wire going to it.

 

[maineplower]

Would that be what they call the load dump relay?

 

[mg2361]

Yep. On the Deere "LC" series they called it the shut down relay, starting with the Deere "CLC" series they called it the load dump relay.

 

[maineplower]

Thanks I’ll check it out

 

[maineplower]

I changed the relay no change. Could it be something to do with the alternator back feeding the machine after the key is off? The key shuts everything off like the heater fan etc properly when the engine isn’t running, as soon as engine is running key doesn’t shut things down.

 

[mg2361]

It is the diode that needs to be checked, not the relay.

 

[maineplower]

Where is the diode?

 

[mg2361]

See post #2

 

[maineplower]

Found them. Swapped it with another and it works. Have to get another Monday from the dealer. Thanks for your help

 

[maineplower]

This worked fine for a few works, now won’t shut off with key again. What would cause the diode to fail?

 

[mg2361]

Overcurrent. You might have a short in the circuit somewhere after the diode.

 

[maineplower]

Like the alternator is overcharging?

 

[mg2361]

No. An intermittent dead short of the wiring to ground "after" the diode is more likely the issue.