Odd electrical problem with 312-A

[davem1111 2,030]

So, I just finished replacing the hydro pump on my 312-A, and replaced the gas tank valve, filter and most of the fuel line. I had suspected that the original fuel pump was dying or dead around the time that the hydro went. In anticipation of having to fix *this* problem, I ordered a Carbole 12v fuel pump (I've had one running on my 416-8 for a few months now and it works great. Yeah, I know, not American made, but my budget couldn't handle the ones that are...).  Anyway, today I tried starting it and wasn't getting any fuel to the carb so I pulled the lines and installed the Carbole pump up front where the original is. Tapped into the ground for the headlights, and ran the positive wire down along the choke and fuel lines and back past the battery. Here's where the trouble seems to start.

 

On the 416-8, I used a toggle switch for a while for the fuel pump, but recently wired it into the bank on top of the panel circuit board. In this case, after some testing with the voltmeter, I tapped into an orange wire that runs through 2 of the punch-down grooves using a crimp fitting like is used for tapping into wires for trailer wiring. This wire had juice with the key on, but none when off. Works great. Here's a picture of that "tap in" (yeah, the punch-down on the right had come up some in this picture - I pushed it down in again):

 

 

Wiring is different on the 312-A, plus there was a lot more crud (and apparently, corrosion) in those punch-down grooves. I cleaned it with a wire brush and an old toothbrush, then did some testing. Looked like the red wire in the second position from the right (looking toward the back of the tractor) was hot when the key was on, but there wasn't enough slack to use a crimp fitting on the wire as it was, so I pulled the wire from the punch-down and used a wire nut to "three-way" it with the positive lead from the fuel pump. I put the third wire from the wire nut back into the punch-down position. The fuel pump does now work, coming on when the key is turned on, and the engine runs. This wire, by the way, is the red one that goes to the key switch.

 

HOWEVER, a bunch of other stuff doesn't work now.  Nothing on the indicator lights panel works, and the headlights don't work (they did before... taillights are still disconnected because rear fender is still off).  Interestingly, the hour meter *does* work, at least, I can hear it ticking.  But I also noticed that even if I pulled the wire back out of the punch-down, the fuel pump and hour meter still run so obviously they have power without the circuit board coming into play... not really a surprise on the part of the pump since the wire is the hot lead from the key switch. Honestly, I'm not sure if anything on the circuit board (the indicator lights or the test switch) was working before all this. I don't think I ever used the test switch or saw any lights come on there, just didn't notice.  So I'm thinking that  1) my circuit board was already dead before all this, or 2) I destroyed the corroded contacts in the punch-down slot when I tried putting a wire back in it. Looking with a magnifying glass, I don't see any metal contacts and there was no penetration into the jacket of the wire when I pushed it down.  Here is what that all looks like, voltmeter probe pointed to the punch-down slot:

 

 

I even tried stripping the end of the wire to see if I could get any contact and response from the circuit board, but... nothing. I just did a quick look on the Googles to see if there are boards available and didn't find much yet. I did notice a thread on this forum from 2012 about re-manufactured boards and even a replacement with an LCD digital dash (very cool). 

 

Wondering what your thoughts are, and what the recommended approach might be to fixing this, and what the implications are if I just ignore it (engine runs, but obviously those indicator lights come in handy at times).  This wouldn't effect the functions of the seat switch/engaged clutch ignition cut-off or anything like that, would it?

 

Heading to bed now so I won't be responding tonight, but any advice is surely appreciated.  Thanks -Dave

 

 

 

 

 

 

 

 

 

 

Edited April 4, 2022 by davem1111

[953 nut 55,228]

8 hours ago, davem1111 said:

I don't think I ever used the test switch or saw any lights come on there, just didn't notice.  So I'm thinking that  1) my circuit board was already dead before all this, or 2) I destroyed the corroded contacts in the punch-down slot when I tried putting a wire back in it. Looking with a magnifying glass, I don't see any metal contacts and there was no penetration into the jacket of the wire when I pushed it down.  

I even tried stripping the end of the wire to see if I could get any contact and response from the circuit board, but... nothing. I just did a quick look on the Googles to see if there are boards available and didn't find much yet. I did notice a thread on this forum from 2012 about re-manufactured boards and even a replacement with an LCD digital dash (very cool). 

 

Wondering what your thoughts are, and what the recommended approach might be to fixing this, and what the implications are if I just ignore it (engine runs, but obviously those indicator lights come in handy at times). 

I have never owned a Wheel Horse with the idiot lights and since you have been ignoring them in the past I don't see why you are concerned about them now. It starts and runs and the safety switches work, be happy!           

[biged77 113]

The "punch-downs" are the weak link for the circuit board operation.  I had a bad connection on one of my tractors and it took several iterations to get it to work.  As for the headlights not working I see nothing you have done at the circuit board that would affect the lighting circuit.

[gwest_ca-(File Mod) 11,041]

The engine may have to be running for the headlamps to work.

The model number of this 312-A would help.

[davem1111 2,030]

24 minutes ago, gwest_ca said:

The engine may have to be running for the headlamps to work.

The model number of this 312-A would help.

 

Hmmm... I'm pretty sure the headlights worked with just the key turned on before, but I could be wrong.  I just got this tractor back into running condition but only ran it for about 10 seconds, because I need to test the "new" hydro pump.

 

This is what the model number lookup gave me: 21-12KE03 1987 Garden Tractor 312-A Automatic Kohler M12S-471527.  Thank you @rmaynard for uploading the document with all the serial number lookups! 

(I thought my 416-8 was an 86 or 87, but it's actually an 89:  31-16O801 1989 Garden Tractor 416-8 8-Speed Onan P216G-I/10779B).  On the 416-8, the lights definitely come on without the engine running, but that doesn't mean they should on the 312-A. 

 

I wish I had a better idea of what is underneath these corroded contacts, because I'm thinking now I may try to do some scraping and soldering to overcome the corrosion and weak or non-connections. When using the voltmeter on the 416-8, if I remember correctly, everything that was "live" measured over 12 volts, but on the 312-A I was getting some weird readings around 2-3 volts. Maybe that's a sign that the circuit board is just fried.

 

Has anyone tried soldering the connections on the circuit board?   Any replacements out there?  I haven't found any yet.  

 

Oh, and does the electrical system on these tractors recharge the battery while running?  I'm having a problem with a relatively new battery constantly going dead on the 416-8. 

 

[Handy Don 12,218]

I've never heard of an electric start WH that wasn't supposed to charge its battery! Kinda "elementary Watson", right?

I have heard of lots, including one of mine, that needed work on the electrical to get all the contacts clean and sometimes, as in my case, a new voltage regulator.

One regular "fail factor" is an exhausted battery. The only way to find this out is a load test at a battery dealer or good service facility (age isn't a consistent indicator of battery health).

[953 nut 55,228]

Your voltage regulator is on the flywheel cover. There should be 12 volts DC on the center lead with the key on. With the engine running there should be 36 volts AC +/-  between the two outer leads.

[gwest_ca-(File Mod) 11,041]

Being a 1987 model 312-A your lights should work without the engine running - 15 amp charging system.

 

[clueless 2,991]

On 4/4/2022 at 5:58 AM, 953 nut said:

I have never owned a Wheel Horse with the idiot lights and since you have been ignoring them in the past I don't see why you are concerned about them now. It starts and runs and the safety switches work, be happy!           

I've said this before, I find it funny that the safety lights (idiot lights) on these tractor seem to be the first things to quit working.  IMHO waste of wiring.

[peter lena 8,625]

@953 nut , referring to your engine cooling tin drawing . made a point of using contractor electrical bolt on lugs to my enhanced grounding set up . that at mid point of , battery cable ground bolt cable , to engine / frame corner , to  regulator bolt s , to headlights  . completely stopped my  electrical issues . keep it grounded , pete

[davem1111 2,030]

22 hours ago, Handy Don said:

I've never heard of an electric start WH that wasn't supposed to charge its battery! Kinda "elementary Watson", right?

I have heard of lots, including one of mine, that needed work on the electrical to get all the contacts clean and sometimes, as in my case, a new voltage regulator.

One regular "fail factor" is an exhausted battery. The only way to find this out is a load test at a battery dealer or good service facility (age isn't a consistent indicator of battery health).

 

Pretty sure I still have the receipt, and the people at Rural King are unlikely to question it, they'll probably just let me grab a new one. But, that's a bit wasteful. Maybe I'll try that battery in the other tractor and see what happens. But I'm also going to test the regulator.    But I think I'm confusing things by talking about both tractors in the same thread.  The battery keeps dying on the 416-8.  The 312-A is still up on jack stands with an untested hydro in it. Not enough hours in the day to get to all this...

[Handy Don 12,218]

Ideally, there is someone who can load test for you. I'd hate to condemn an ok battery!

 

As for voltage regulators, you'll see Onan parts pricing mentioned in plenty of threads. An OEM regulator will go dear but several of us, including me, have used 3rd party ones successfully. The only glitch I encountered was that mine (~$15) didn't come with a mounting screw as advertised. Luckily, I had an M5 screw so all good.

[davem1111 2,030]

2 hours ago, Handy Don said:

Ideally, there is someone who can load test for you. I'd hate to condemn an ok battery!

 

As for voltage regulators, you'll see Onan parts pricing mentioned in plenty of threads. An OEM regulator will go dear but several of us, including me, have used 3rd party ones successfully. The only glitch I encountered was that mine (~$15) didn't come with a mounting screw as advertised. Luckily, I had an M5 screw so all good.

 

I used to work in computer data centers a lot, and they use a lot of M5's for rack mounted units. I have bags of them 

 

I had a few minutes to look at the 416-8 punch-down, and the wire that I tapped into is the orange one, which from the picture that @gwest_ca posted a link to is one of the ones that goes to the regulator. Most likely I messed up it's connection at the punch-down.  Will probably not have much time to mess with it any more till this weekend, but I think I'm going to do some soldering. 

Edited April 6, 2022 by davem1111

[Handy Don 12,218]

16 minutes ago, davem1111 said:

lot of M5's

16 minutes ago, davem1111 said:

think I'm going to do some soldering

One of my sons-in-law introduced me to paste solder that he applies with a heat gun instead of an iron to repair or patch sensitive circuits where he doesn't want to lift the foil or overheat nearby components. Since you clearly know which end of a soldering iron to hold, thought you might find this intriguing 

[davem1111 2,030]

Two things, as an update to this thread:

 

1. On the 416-8, I re-did the wiring I hacked in to connect the fuel pump, this time soldering the junctions and covering them with rubber caulk.  Then I noticed that on top of the Onan 16 just in front of the battery, there was a spade connector that had come loose from what may be the voltage regulator for this tractor. I put it back on.  Now when running, the battery is, if anything, showing a bit higher voltage than when off. I didn't test this very scientifically...  I guess what I should do is identify the exact points where I should be testing for "charging" voltage, but the wiring diagrams have me scratching my head about what goes where, and the wire colors don't seem to match what the diagrams show.  This is a 1989 416-8, and the diagram I have says it covers both the 312 and 416, which I'm starting to doubt (at least, for the correct year and model. 

 

2. On the 312-A, it turns out that for some reason, the bolt on the hood that the ground wire connects to had lost connectivity with the hood metal to provide a proper ground. I just ran another ground wire from both headlights to the ground wire on the engine side, and now the headlights are working fine.  I also removed the circuit board, and noticed that several of the edge connectors had gotten so corroded that there was no way they could make contact with the molex edge connector that the wiring is punched into. So, I cleaned the board a bit and found enough copper trace to solder new wires to, and just ran them out around the side to connect with the correct wires that I pulled from the punch-down. Still, the only LED that works when the test switch is thrown is the Engine Oil one. Ah well, probably not worth messing with unless I decide to try to do a restoration on this tractor. If I do that, I'd like to get everything working, which may not be realistic unless I can get a replacement circuit board.  I am still having problems with the hydro pump, and since I have the tractor pulled halfway apart for that, I may just do a teardown and some serious cleaning and re-painting. More likely I'll wait until I at least semi-retire when I'll have more time for a project like that. 

[gwest_ca-(File Mod) 11,041]

1988 312-8 and 416-8 is the same because they both used \Kohler engines.

 

Made some revisions to this file April 13, 2022