x749 garden tractor electrical problem

dapg · Aug 18, 2016

I have a JD x749 garden tractor with a fuse block with three 15 amp fuses and one 30 amp fuse. My son was using it recently and he told me that it shut off 3 or 4 times when the temperature gauge showed overheating. He let it cool each time and the tractor would restart. I cleaned grass etc debris from the radiator and ensured that the air filter was clean. I removed the mower deck and attached my sprayer. I ran the tractor for about 10 minutes and then it died, blowing one of the 15 amp fuses (the fuse unrelated to the headlights, and unrelated to the dc accessory socket running the sprayer). I changed the 15 amp fuse several times and it kept blowing- initially after a minute or two of starting the tractor, but then more quickly. Now it is blowing the 30 amp fuse repeatedly despite normal operating temperature on the temperature gauge. The tractor dies even without an implement running. When I replace the 30 amp fuse and turn the key the dash lights come on. When I turn it further to start the tractor the tractor starts, but immediately dies with loss of the dash lights. Any thoughts?

roostershooter · Aug 19, 2016

I'd check for a possible short in the wiring first of all. Maybe a wire rubbing on metal.

turbo36 · Aug 19, 2016

These models are notorious for fuse block corrosion and failure. I had the same issues and replaced the fuse block with individual inline fuses.

jenkinsph · Aug 19, 2016

I had similar problems early this year and a mechanic at the dealer recommended changing the battery. With some reluctance I changed the battery and no problems since for about 5 months.

Richard001 · Aug 23, 2016

Wow, I'm speechless. Fuses are blowing because of a bad battery?

Maybe those old worn out electrons just didn't feel like working any more so that just ganged up on the fuses.

jenkinsph · Aug 24, 2016

Richard001 said:
Wow, I'm speechless. Fuses are blowing because of a bad battery?

Maybe those old worn out electrons just didn't feel like working any more so that just ganged up on the fuses.

No, the new electrons don't know about jumping off the beaten path. And I am not going to tell them either.

Prior to changing the battery I had cleaned the fuse block terminals and installed new fuses. I had also checked the fuse contacts to the fuse block terminals suspecting a bad connection to no avail. Cleaned the battery terminals and looked over all the wiring to see if there was any place that had rubbed and shorted. Still kept blowing fuses intermittently. Battery voltage readings appeared normal, both running and stopped, the 40A alternator seemed to keep the battery fully charged. All connections I could get to were checked and tightened.

I gave up and called the dealer and spoke with a mechanic and he recommended changing the battery which was 6+ years old. I installed a new battery group 51 (IIRC) from Walmart and no problems since. It has worked all spring and summer with out a hiccup.

Now the only thing I can think of is that if the battery had an intermittent open or high resistance that the voltage could spike in the charging circuit. Don't know, just a guess but there is a lot of equipment out there that can be ruined by running and allowing the battery to be disconnected momentarily. Mercury outboards are a good example.