[halfhalt]

Have been troubleshooting my JD5400. Last month replaced key switch, starter relay and diode module. Tractor then started and ran fine for a few days. Now, it's blowing the main 30 amp fuse for the injector pump when I turn the key to the ON position. I've done a cursory inspection of wiring behind the dash and haven't found anything obvious.

Discocnnected the power feed to the injector pump solenoid. Checked resistance between that wire and ground. Approx 20 Ohms. Turned key to ON while disconnected. Blew fuse. Traced wire through tractor in attempt to find a rub in the insulation. In most places the wire is enclosed inside corrugated protective tube. Short of removing that tubing I cannot do any better inspection. Found no visible issue with that or any other wire I could visually inspect. Moved on to eliminating other possible sources of a short. Removed the two relays (one I believe is for injector pump solenoid, other for headlights). Still blew fuse. Removed diode module (replaced with new during last month's repairs). Fuse blew. Considering gauges are powered up when key in ON position, disconnected dash module. Fuse blew. Replaced key switch with new. Fuse blew. Went to store and purchased additional 30 amp fuses!

There is one more known relay over near the starter I have not yet isolated and tested. I may try to rule it out also. After that I have no other ideas.

Any suggestions?

 

[Tx Jim]

Welcome to GTT
Disconnect battery ground cable from frame. Insert test light between cable & frame. When ign switch is energised with a good fuse test light will illuminate.Start disconnecting electrical components 1 at a time & when light goes out short should be identified

 

[workinonit]

So you lifted the wire from the fuel shutoff and it still blew?

 

[halfhalt]

Welcome to GTT
Disconnect battery ground cable from frame. Insert test light between cable & frame. When ign switch is energised with a good fuse test light will illuminate.Start disconnecting electrical components 1 at a time & when light goes out short should be identified

I will give this a try. Up to now I've been disconnecting one component at a time and blowing through fuses (pun accidental). Thank you.

 

[halfhalt]

So you lifted the wire from the fuel shutoff and it still blew?

Yes. In addition, I’ve now disconnected every other electronic sensor or module I can find. Still blowing fuse.