2166 Blowing fuses

blackcloud77 · #1 10-04-2021, 04:39 PM

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 · #2 10-04-2021, 06:13 PM

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 · #3 10-04-2021, 09:27 PM

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 · #4 10-05-2021, 10:33 AM

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 · #5 10-05-2021, 11:45 AM

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 · #6 10-08-2021, 05:35 AM

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

blackcloud77 · #7 10-11-2021, 05:27 PM

Well, I spent all day tearing into the thing, expecting to find something obvious in the headlight lines. Nothing to be found.

Turns out this is not the fuse I thought it was, seems we're on the positive side, which makes sense if we are shorted to ground and blowing fuses. At least according to the wire colors. And the wire colors don't match the schematic, either. It looks factory but it's got red and red/white wires going to the fuse holder in question; the schematic indicates red, then black going to the switch. The red/white is going to the switch.

I thought I was on the right track, I found continuity to ground from one side of the fuse holder, and traced that through the harness. I suspected the wiring passing through the engine going to the ignition and voltage regulator, but after fighting with it for hours, I found that the continuity was from the oil sensor and carburetor solenoid. Both of these leads went to ground, I'm not certain or not whether they should. Removing the leads from each broke their connection to ground. I assumed this was correct and buttoned everything back up, giving up for the day.

I am starting to think now that the fault could be anywhere in the harness and I'm not sure I have the patience to go through the entire thing. The new harness is $180 and if I knew that's what it would cost to fix it...I'd pay that in a heartbeat.

Any new ideas to indicate something to check or go a different direction, I'm all ears!

Billy-O · #8 10-12-2021, 07:24 PM

Did you test the switch?? I'm judging this from your very first post...."One day I found that the tractor would not start....". The blown fuse was just an intermittent problem which got worse and maybe the switch was failing. Disconnect the wires from the switch and test it. If ok, then start testing the wires and follow it. Better to do this disconnected from switch. Find the one that may have continuity to ground and follow along it. Keep in mind, one wire goes to the switch as ground from headlights as per schematic. Let's start with this for now.

As for buying a new wiring harness..... You could very well blow $180 and find out that it didn't solve your problem.

blackcloud77 · #9 10-14-2021, 07:13 PM

I haven't tested the switch, I suppose I just felt that the logic was sound that the switch is OK because the fuse did not blow if I got it to the start/run position before it had a chance to do so. Fair enough though, $40 vs $180.

The problem I always have is that the tractor is at my father-in-law's house 45 minutes away, where I have to do the mowing. So I have time to do all the poking around on the internet but very little time to test and tinker. That's part of the reason why I'm inclined to just buy new parts while eliminating them as causes of the problem. And also why I just ordered a switch instead of testing the old one.

A wiring harness is on its way too, but after 3 days the folks at Cub Cadet Parts N More have not changed the status of my order from "Processing." So the switch may just beat the harness to my mailbox, and if that fixes the problem then the harness might just go back. But in theory a new harness should eliminate the need for the relay band-aid, too. We'll see how that goes and how much I miss the money.

One thing I did find that was curious, there was what seemed to be a non-factory wire from the voltage regulator's mounting screw to the engine. I don't see this part grounded on any of the diagrams. I may remove it, but I have to assume it was put there for some reason, it looks well done and has nice terminations on it.

guyina4x4 · #10 10-14-2021, 10:36 PM

The voltage Regulator needs the ground wire. It had one from the factory.

I've not seen any 2000 series that didn't have intermittent electrical problems.

Key switch and pto switch are most common failures other than gremlins.