Main fuse keeps blowing. Why?

Michael526 · Jul 3, 2004

I just took my brand new New Holland TZ24 out for its first day of work. Everything was going great, after a couple of hours the gauge indicated it was getting low on gas so I drove it on the trailer, turned it off, went to the gas station, filled it up, brought it bac k to my lot, but it wouldn't start. None of the gauges, lights worked or anything. After a thorough exam, I figured out the main 40amp fuse was blown, so I drove to the auto store to get 2 more, one for a spare. Replaced the fuse, and all the lights and guages came on, but when I went to start it up, it wouldn't start, and blew that fuse also. Same thing with the third fuse. Of course, its saturday afternoon so the dealer is closed, will be tomorrow also, and probably on Monday as well. Anybody know what is going on? I know nothing about vehicle electrical systems.

Bird · Jul 3, 2004

</font><font color="blue" class="small">( Replaced the fuse, and all the lights and guages came on, but when I went to start it up, it wouldn't start, and blew that fuse also. )</font>

You did turn off all the lights before trying to start it, didn't you? That would reduce the current draw a bit. But then I'd be looking for a short somewhere or something loose.

beenthere · Jul 3, 2004

To find a short, I wire up a light bulb (I suppose a 40 amp in this case) to the shorted fuse, with two wires soldered to each side of the bad fuse and to each 'side' of the light bulb (tip and side). Then when plugging this bulb arrangement into the fuse slot, it will light as long as there is still a short. Makes finding the short easier by going around and wiggling wires (hopefully that works) or disconnecting wires until the rigged light goes out. Then you have found the short.

bgott · Jul 4, 2004

That works but you're stuck with line of sight. Yank that pesky seatbelt buzzer out from under the dash of your truck, add a couple of pigtails and use it the same way. You can hear it rather than have to see it. It can, however, be annoying when you have one of those shorts that take a good while to find. Once you have your short finder rigged on the main fuse start pulling the other fuses one at a time to figure out what circuit the short's on.

You don't need a 40 amp bulb, the short is the ground, you're not looking for current carrying capability. If you use too high an amperage bulb or buzzer on a low drain short you might not have enough of a ground to operate the tester.

If you can't find the short with these methods you can always jumper the fuse holder and then look for the smoke. /forums/images/graemlins/grin.gif I would not do this on a unit you have any expectation at all of getting serviced under warranty. It is not a recommended method but I have seen it done in frustration.

beenthere · Jul 4, 2004

I like the idea of the buzzer. Also, thanks for the size of lightbulb tip. I wasn't sure. I used the lightbulb because I could see it, as opposed to the volt meter that I could only look at directly.
I've used my test bulb several times, and once it was a wire that shorted out in the headliner of a Citation I had. After many tries to find the short, I just happened to hit my head when getting out of the car, when the 'light' went out (test light that is /forums/images/graemlins/smile.gif ). Otherwise, I probably never would have found it. And a short is not something one wants to turn over to a car dealer service crew to 'search' for, at their prices per hour.

KiotiJohn · Jul 4, 2004

Sounds like you have a direct short at the starter. Check all of the connections from the starter, alternator and battery. As you said, it didn't happen until you tried to restart. Look for an open wire touching on the tractor where it shouldn't. I wouldn't get too involved though as you don't want to do anything that would void the warranty. John

Inspector507 · Jul 4, 2004

umm........What's a 40 amp light bulb........?? /forums/images/graemlins/grin.gif

Michael526 · Jul 4, 2004

Thanks for the help. I was hoping it would be something easier for me to fix, but wiring and electricity is something I never picked up. Guess I'll be taking it to the dealer tomorrow.

bgott · Jul 4, 2004

You know, something about that kind of bugged me when I read it last night but, obviously, it flew right over my head! /forums/images/graemlins/grin.gif

"umm........What's a 40 amp light bulb........?? "

A great freakin' big one!!! /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif