# john deere lt155



## jd155 (Jun 26, 2021)

i just got a john deere lt155 from a buddy of minei noticed that the wires 
at the voltage regulator are melted in the connector and get real hot and smoke
when running the eng.it has the kohler 15hp ohv eng what could be my prob.


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## Bob Driver (Nov 1, 2017)

It's a rectifier/regulator..... The stator under the flywheel produces *AC* current that flows into the rectifier/regulator through the two OUTSIDE terminals. It's a 1/2wave rectifier and converts the output to DC current coming out of the center terminal. If the terminals have melted the stator windings have gotten hot. With a DVOM, check that there is no continuity between the two outside wires and there is no continuity to ground on either wire. If there is, the stator windings are burnt...... Aftermarket stators run $35 to $50


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## jd155 (Jun 26, 2021)

Bob Driver said:


> It's a rectifier/regulator..... The stator under the flywheel produces *AC* current that flows into the rectifier/regulator through the two OUTSIDE terminals. It's a 1/2wave rectifier and converts the output to DC current coming out of the center terminal. If the terminals have melted the stator windings have gotten hot. With a DVOM, check that there is no continuity between the two outside wires and there is no continuity to ground on either wire. If there is, the stator windings a burnt...... Aftermarket stators run $35 to $50


thank you for the info it was .very helpful


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## Bob Driver (Nov 1, 2017)

jd155 said:


> thank you for the info it was .very helpful


Might as well change them both, if the stator is shorted

CV15 Charging Kit


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## jd155 (Jun 26, 2021)

ok got new stator an regulator instaled seems to be ok stll gets a little 
warm but has not got so hot it melts the wires but it seems to not be 
charging any help


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## Bob Driver (Nov 1, 2017)

Center terminal on the rectifier/regulator should be the output. Measure voltage there. Should be 13.2, or better, at an idle. If not, try running a separate ground wire to the engine and don't trust just the rectifier/regulator mounting screws for adequate ground. Kohler is notorious for bad grounds through the rectifier/regulator mounting screws. Once you're getting 13.2 or better at the output terminal, follow the lead up to the next junction. Should be at the contstant "hot side" of the two big terminals on the starter relay (Wiring diagram below shows a fusible link that could be blown). If the link is good, shouldn't see more than .5V drop. If you do, clean the terminals, or make a new lead out of heavier gauge wire. From the starter relay, next junction should be the "B" terminal at the key switch. Measure voltage(eliminate any drop). At the key, L, A1, A2 are the "through put" terminals for DC voltage on that 4-position switch. Big voltage drop at any of those terminals is a corroded key switch.

JD 155 Wiring


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## Bob Driver (Nov 1, 2017)

Make sure both terminals at the battery are clean/tight and I've always had better luck running the battery ground to the actual engine and not the chassis of the unit.


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## jd155 (Jun 26, 2021)

ok i have 12.51 volts at idal good ground .fuseable ling good still gets warm all wires good 
an tight i have charged batt to full charge i checked ign. switch terminals thay are clean no
carosion not sure what is going on might just have to jump start when i neet to mow


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## Bob Driver (Nov 1, 2017)

12.51 at idle is battery voltage.... Doesn't sound like your new stator is putting out. Take a multi-meter and put it on* AC voltage*. Put the multi-meter leads the between the two leads coming off the stator to read the AC voltage (should be white leads on a Kohler). Needs to be a minimum of 28 volts AC even at idle and can go above 40 at full throttle. Once again, it is critical that the rectifier/regulator is well grounded.


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## jd155 (Jun 26, 2021)

Bob Driver said:


> 12.51 at idle is battery voltage.... Doesn't sound like your new stator is putting out. Take a multi-meter and put it on* AC voltage*. Put the multi-meter leads the between the two leads coming off the stator to read the AC voltage (should be white leads on a Kohler). Needs to be a minimum of 28 volts AC even at idle and can go above 40 at full throttle. Once again, it is critical that the rectifier/regulator is well grounded.


thanks agian for the info i will ck this out an let you know how it goes 
thanks for the wireing diagram i need to find a site that will let me print out 
a owners manual every one i go to wants to charge you


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## jd155 (Jun 26, 2021)

ok back to the mower i was just checking and with a test lite
key off or on i have voltage at all termanals at the regulator so 
now what?


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## jd155 (Jun 26, 2021)

there is voltage at red center wire key on or off and with it pluged to regulator or un pluged
from regulator and voltage is gone from the 2 white wires i droped my volt meter so thats
way im useing test light


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## Bob Driver (Nov 1, 2017)

The red wire on the regulator ties into the battery at some point to charge it. What your reading is battery voltage. Can't check the white wires with a test light.... They're AC VOLTAGE


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## jd155 (Jun 26, 2021)

got new meter ran test to both white wires both show 28.5 center shows 13.2 and batt voltage 12.75
seems like the brown wire on left outside terminal that ties in to white wire from stator gets hotter then the other
side


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## Bob Driver (Nov 1, 2017)

If these numbers are at an idle, they're good. 28.5 VAC on the white wires is good, 13.2VDC on the center(red) is good(at Idle) That means both the stator and rectifier/regulator are working...... Your getting a .5VDC drop between the rectifier/regulator and the battery, that's to much(13.2 to 12.75). Trace that wire to where it connects into the battery, I believe it was at the "hot side" of the starter relay, but I've slept since then. There was also either a diode, or fusible link, that protected the stator from feedback at the battery. Somewhere along that path, is where you're losing that .5VDC. Clean the connections and use your DVOM to find the voltage drop. Here's a PDF that shows how to use your DVOM to find the voltage drop in a circuit. 

Voltage Drop Test

That Brown wire probably goes to some sort of "Shunt Relay". It's getting hot because, for some reason, it is "shunting" 12VDC voltage to ground. John Deere likes to tie those into the safety switch circuits. That's a whole other issue to work through. You need to work on the voltage drop problem first and then we can troubleshoot the "shunt" problem.


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## jd155 (Jun 26, 2021)

Bob Driver said:


> If these numbers are at an idle, they're good. 28.5 VAC on the white wires is good, 13.2VDC on the center(red) is good(at Idle) That means both the stator and rectifier/regulator are working...... Your getting a .5VDC drop between the rectifier/regulator and the battery, that's to much(13.2 to 12.75). Trace that wire to where it connects into the battery, I believe it was at the "hot side" of the starter relay, but I've slept since then. There was also either a diode, or fusible link, that protected the stator from feedback at the battery. Somewhere along that path, is where you're losing that .5VDC. Clean the connections and use your DVOM to find the voltage drop. Here's a PDF that shows how to use your DVOM to find the voltage drop in a circuit.
> 
> Voltage Drop Test
> 
> That Brown wire probably goes to some sort of "Shunt Relay". It's getting hot because, for some reason, it is "shunting" 12VDC voltage to ground. John Deere likes to tie those into the safety switch circuits. That's a whole other issue to work through. You need to work on the voltage drop problem first and then we can troubleshoot the "shunt" problem.


think i found it the shunt relay inside therelay was stuck togather and shorted i will get new relay and give it a try


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## Bob Driver (Nov 1, 2017)

Good stuff..... Sounds like you're about to get it. Once you replace that defective shunt relay, the voltage drop will probably go away and you've solved the problems


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## jd155 (Jun 26, 2021)

Bob Driver said:


> Good stuff..... Sounds like you're about to get it. Once you replace that defective shunt relay, the voltage drop will probably go away and you've solved the problems


thanks for all your help i probley would not found it with out your help .got new relay on works great also i found 
carosion on the termanels at the key switch so i cleaned that all up too again thanks


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## Bob Driver (Nov 1, 2017)

Success!!!!!! Grandpa used to tell me..... "Kid you gotta be smarter than whatever you're workin' on and you're the only one that can read between you and an inanimate object ". Sadly, I have to admit there have been several times in my life when I've actually been outsmarted by a $.50 light bulb


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## bontai Joe (Sep 16, 2003)

We all love a happy ending. Good job for both of you!


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