5075E blowing start fuse when turning key

[thepumpguysc]

You may have gotten ahead of yourself.. excited that you found the answer to your problem, unplugged the sensor, replaced the fuse & tried to start it.. I'll bet something is in gear?? PTO on?? Wiggle your shifters while HOLDING the key switch to "start".. its probably something simple.
You can always jump the starter w/ a wire or screwdriver or the proper tool, a remote starter button, to make sure its not the starter..
Make DARN SURE its not in gear or it'll run you over.!!

 

[Robmoss]

Thankyou. After wiggling the shifters and taking the plugs apart and putting them back together the tractor started with the key, safely.

 

[thepumpguysc]

Thanks for reposting.. glad ya gottr straightened out..

 

[Ferndale]

Thank you for this advice, I had the same problem on on my new 5075, only done 400 hours. It kept blowing the starter circuit fuse and turned out to be a dead short in the temperature sensor RE503242. With the sensor disconected the tractor would start but sounded very rough, fitted a new one and cold starting is back to normal. The JD dealership have promised to replace the sensor under warranty but after two weeks waiting I decided to order the sensor from abroad and do the job. Thanks once again for great advice.

 

[CobyRupert]

Related question regarding priming a 50x5E series Deere:

When you drain (or bleed off any water that may be in) the fuel filter by opening the port on the bottom of the filter, how does this not introduce air into the filter?

Should you only drain filter with shut-off valve into filter open?

 

[Ferndale]

Related question regarding priming a 50x5E series Deere:

When you drain (or bleed off any water that may be in) the fuel filter by opening the port on the bottom of the filter, how does this not introduce air into the filter?

Should you only drain filter with shut-off valve into filter open?

Probably a good idea to undo the plastic bleed screw on the top of the filter and turn the key on to purge any air out that may have gotten in while you were draining water from the bottom plug. It may just save you having to bleed the injectors.

 

[beenthere]

Related question regarding priming a 50x5E series Deere:

When you drain (or bleed off any water that may be in) the fuel filter by opening the port on the bottom of the filter, how does this not introduce air into the filter?

Should you only drain filter with shut-off valve into filter open?

Procedure outlined in the operator's manual. Do you have one?

 

[CobyRupert]

Probably a good idea to undo the plastic bleed screw on the top of the filter and turn the key on to purge any air out that may have gotten in while you were draining water from the bottom plug. It may just save you having to bleed the injectors.

Turn key? Is there a lift pump upstream of filter?
Removing bleed screw at top of filter may help.

I can see that opening the drain port on bottom of filter opens the inside center of the filter directly to atmosphere.
I guess there's a few things I don't know:

Is filter gravity fed from tank?

Is the inside center of the filter the "in" side of the filter?
Is drain port at bottom of filter relying on gravity fed fuel from tank to "flush" sentiments out, thus preventing air from going in?
I assume the top filter bleeder screw is on the output side of the filter?
I assume the "purge pump" on top of the filter takes fuel from input side /upstream of filter and pushes it through filter?

Procedure outlined in the operator's manual. Do you have one?

Yes.
It basically says "Open drain...close drain."
When I did procedure as per manual, I then had to bleed system from filter to fuel pump (removing bleeder screw and loosening return line at fuel pump on the other side of tractor) for it to start again. Basically, bleed everything except output lines of pump. This was not as per manual.

 

[ElandaleFarm]

I believe the problem is the thermistor sensor (thermistors are temperature variable resistors used as sensors.). On the thermostat housing there is a sensor that is connected to a two wire harness that goes to the injection pump; this is the "cold start advance" portion of the system so it starts easier when cold by advancing the timing.

When the sensor on the thermostat housing fails it shorts out and blows the fuse. Try unplugging it, replace fuse and see if it starts and runs. The part # is RE503242, if you are quick changing it, you don't have to drain the coolant, just make sure it's not hot at the time. You will want a pan under the tractor to catch the coolant, so as not too have to clean it up.

Power never gets to the injection pump when the PTO switch is on before the tractor starts since it is a safety switch, that is why the fuse does not blow.

If you do a search of this site on the part # RE503242, you will find this is a problem on the 3029 engine.

URL to JD parts
jdpc.deere.com/jdpc/servlet/com.deere.u90490.partscatalog.view.servlets.HomePageServlet_Alt

Excellent post. Having the part number & the photo really gives me confidence I'm getting the correct part.

 

[mattraven]

I believe the problem is the thermistor sensor (thermistors are temperature variable resistors used as sensors.). On the thermostat housing there is a sensor that is connected to a two wire harness that goes to the injection pump; this is the "cold start advance" portion of the system so it starts easier when cold by advancing the timing.

When the sensor on the thermostat housing fails it shorts out and blows the fuse. Try unplugging it, replace fuse and see if it starts and runs. The part # is RE503242, if you are quick changing it, you don't have to drain the coolant, just make sure it's not hot at the time. You will want a pan under the tractor to catch the coolant, so as not too have to clean it up.

Power never gets to the injection pump when the PTO switch is on before the tractor starts since it is a safety switch, that is why the fuse does not blow.

If you do a search of this site on the part # RE503242, you will find this is a problem on the 3029 engine.

URL to JD parts
jdpc.deere.com/jdpc/servlet/com.deere.u90490.partscatalog.view.servlets.HomePageServlet_Alt

Thank you for an excellent post - I will add my 5105 to the list where this was the problem. Was working fine after a 600 hour maintenance. Went to start in the woods and nothing. No idea except I figured out when I tried to crank it the Key Switch fuse would blow. Just got back from getting a new thermistor sensor and hope to get it installed in the next day or two. Thanks again for the assist!