Display & Lights blowing fuse after replacing stop relay

[SwingOak]

I have a DK50se HST that has had intermittent starting issues for a few years now. I had replaced the ignition switch and the problem went away for a while, then I picked up spare relays for the ignition and stop circuits from the dealer and then never installed them because the problem went away again.

It had started misbehaving again last week while I was traveling for work, so the only way to get the tractor to start was to directly jumper to the starter solenoid directly from the battery with the ignition key switch on. I was able to coach my girlfriend how to "hotwire" the tractor over the phone.

Today while working on fixing the problem, I disconnected the ignition switch and attempted to hotwire it from the plug, and it wouldn't start. It had to be the relay(s) finally quit for good. I found where I had put the spare relays, and after swapping out one at a time with the replacement I found the stop relay was the culprit. I swapped out the relay, put everything back together, and problem solved.

But now there's another problem - after changing the stop relay, the fuse for the headlights blew. This 20amp fuse is not only the headlights fuse, but also the instrument cluster lights and gauges. I replaced the fuse, started it up, and 5 seconds after turning the headlights on, it blew again.

Any thoughts on what could be causing this? It was working fine until I replaced the stop relay fuse - does this relay have anything to do with the lighting and gauge cluster circuit?

 

[K5lwq]

A wiring diagram would help but I doubt the relay has anything to do with lights. It is more plausible that in the process of disconnecting the switch and trying to use a jumper something is now shortened. I would look closely at the wires around the switch and behind the instrument panel.

 

[SwingOak]

When I thought the ignition switch was bad, I hotwired it to start it for weeks until the new switch came in. No problems then at all, and since. It's been years.

It just seems odd that I could turn the key on and jumper to the solenoid terminal on the starter solenoid from the battery and it would start, and everything worked fine. And as soon as I replace the stop solenoid, poof I start to blow the lighting fuse.

I have fuses, relays, & 20 amp circuit breakers due in tomorrow, I'll be testing some things out and see what I find.

 

[SwingOak]

OK I'm not sure if this was the problem or not, but seeing as I did put the original key switch back in, I pulled the steering column cover and checked the plug connection. It was good, no problems there, but then I noticed there was a bunch of dielectric grease on the face of it, and I wondered if maybe it was causing continuity with two or more 12v wires that weren't supposed to be connected at all. I cleaned both sides of the plug with contact cleaner, blew it dry with compressed air, plugged it back together and replaced the fuse, and surprise - no more fuses blowing. Everything works again.

Did I actually find the real problem and fix it? Was it just a fluke? Some other mystery, yet unexplained? Was it an intermittent fault? A flying short?

The problem appears to be solved - for now...

 

[K5lwq]

Thanks for the update. I imagine you have it licked for now. Good job!

 

[SwingOak]

Apparently, I did not fix the problem. It worked all weekend, then left and when I came home from a business trip and hopped in the tractor, the fuse was blown again. So, I put in one of the 20amp breakers I'd gotten. It hasn't tripped since replacing the fuse with the circuit breaker - at least, not that I know about...