2166 Blowing fuses

[blackcloud77]

Hi all, I'm trying to sort out an issue I've been having on my 2166. One day I found that the tractor would not start, I checked a few things and found that the fuse on the left side of the tractor was blown. OK, no big deal. I was messing around with a couple things and I think one of the battery leads may have touched the wrong terminal, so I figured that's probably what did it. Popped in a new fuse and I was off and mowing. Next time I went to mow, same thing. Popped in a new fuse and mowed the lawn again. Now, the fuse blows as soon as you turn the ignition on.

I don't think it's related, but after the last mowing job I was re-doing the relay mod since the cheap relay I bought was all corroded and I was having to use a remote start button to send 12v to the starter solenoid in order to mow. I suspected that cheap relay as being part of my starting problems, and assumed the blown fuse(s) are unrelated. I thought I might have mis-wired the new relay so I removed the relay entirely. I unplugged the engine connector (the one that's bolted to the plastic shroud) and wire to the solenoid just to try and narrow down the issue...even with all that disconnected...immediately blows the fuse when the key is turned on.

I did some disassembly to see if I could find anything obvious that was worn, corroded, shorting out, etc. I found nothing too awfully suspect.

I am fairly certain that the fuse in question is the one going to the ignition switch's B terminal, then on to the starter solenoid according to the schematic. Correct me if that's not the one on the left side. If I'm wrong there, I'm chasing in the wrong direction. Sadly, I don't recall the color of the wires behind the fuse...that would have been a good confirmation.

I can read the schematic, but I'm probably not aware of all the things and parts that could potentially cause this symptom. Anyone come across anything like this or maybe have suggestions of things to check?

[blackcloud77]

Looking at the wiring diagram again, and thinking out loud. Correct me if I'm wrong, here. I am following +12v being tapped at the starter solenoid, traveling along the red wire, to the problem/symptom fuse, changing color to black and then running to the B terminal of the ignition switch. It would appear this is the primary 12v+ for the entire ignition switch, not sure why they would tap it at the starter solenoid, but whatever.

Would this logical tracing of this circuit indicate that there is likely a short to ground in the red section between the ignition switch and the fuse?

To test, I am thinking to check for continuity to ground on that side of the fuse and if that's the case... I suppose run a new wire from the solenoid to the fuse, or pay the frustration tax and drop $200 on a new harness.

[Billy-O]

You said that as soon as you key the switch on the fuse blows.... So it can't be the wire between the switch and the fuse because it will blow even if you didn't touch the key switch... Start looking at the switch first and move forward. Look for continuity to ground... that is.... the short.

[blackcloud77]

You're right, Billy. Good catch.

Wish I would have looked at the wire colors, it really would help to know which fuse is blowing. Initially I thought one fuse was just for the headlights, and looking closer it looks like (and I think I recall another post saying) its simply one fuse on the positive side and another on the negative side. If we can confirm which one the left side fuse is, it will be a lot easier to start troubleshooting. I think I should be able to identify (if I don't have the diagram handy, as is usually the case) which fuse is which, one of them will have one side of the socket with +12v ALL the time if I am reading the diagram correctly.

I distinctly recall the fuse blowing on the first clockwise detent of the ignition switch (headlights on), but that doesn't really indicate much because I think EVERYTHING would be on in that position. If I felt like wasting another fuse, I could try inserting the fuse with the switch already in the run position (headlights off) and that would isolate the headlight circuit if the fuse doesn't blow. I suppose it's possible because turning quickly past that position to start as I normally do might be how the fuse survived some mowing jobs. That theory seems valid enough to waste a fuse, I need to buy more anyway.

AvE (on YouTube) is right. Sometimes you need a sit and stink about the situation to figure out what to do next, and throwing it out to the internet for ideas is helpful to clear the log jam inside the head.

[Sam Mac]

2000 series are notorious for head light wiring shorts. They burn the wiring in the headlight area because of the proximity of the exhaust. BTDT.

[blackcloud77]

That's the kind of sage experience I had been hoping to hear, giving some confidence in the troubleshooting direction. Thanks Sam!