Calling all Wheel Horse experts! 416-8.

T.R.K. · Mar 18, 2015

Working on a 416-8. It has the row of red led lights on the dash that tell if the safety switches are made or not.

Three of those lights are on when the switch is off.

Something was killing the battery when the switch is off. I have traced the current drain to that circuit board behind those lights. That circuit board has continuous power from the battery at all times. If I disconnect the wire from the ignition switch to that circuit board my current drain goes away.

How do those lights work? Is this problem in the circuit board- like a bad diode- or is it in one or more of the safety switches? Surely I am not the only one to have ever seen this problem.

Thanks!
Kelvin.

joe csuti · Mar 19, 2015

It would help if you posted eng make/model#.

The early 416's used a kohler K341 which was later replaced by a kohler M16,in addition tractor was also made with an onan P216 twin and there are probably wiring differences between single/twin versions.

I have a wiring diagram of the single cyl version which uses a combination of +12v & -12v to light different lamps on idiot light bar unfortunately wiring diagram I have doesn't have a legend for lamps on light bar.

Looking at wiring diagram for 1 cyl version it appears seat safety sw provides -12v via a red wire to terminal #11 on light bar while all the other inputs to light bar appear to be +12v,try unplugging connector for seat sw & see if that cures problem it's possible seat sw bad or red wire shorting to chassis somewhere in wiring harness,if seat sw/red wire not the problem I would suspect a bad test sw as same is a dpdt sw and one/both poles in sw may be sticking/bad & contacts not opening on one/both poles or you have bad diode(s) on light bar board.I don't have a wiring diagram for twin so I can't help you with that.

gab · Mar 19, 2015

I've got a 518 and 520 Wheel Horse, one has 6 lights and one has 8, wiring diag. is the same on both, just shows light module plug and not the module.
Does yours have test switch on the light module?, that wire to the switch is hot all the time, maybe it got kneed or kicked and is jammed on.
I've never seen a 416 so don't know where the module is.

T.R.K. · Mar 19, 2015

Joe,

this is the '86 version with the K341. I have also had my hands on a '90 version with the M16 and am also working on a '93 version with the Onan on it at the dealership where I work. I guess Wheel Horse didn't want to waste a good model number, but is sure does cause confusion.

I am leaning toward a bad diode too. Or else a short or a ground around the circuit board-it being exposed and all. That board is obsolete.

What we ended up doing since everything worked otherwise, was put a relay in the circuit that feeds power to that board. The relay is powered off the coil wire so it will only connect the board when the switch is 'on'.

joe csuti · Mar 20, 2015

Kelvin,

Glad to hear you found a simple fix with relay rather than getting involved with board especially if board obselete/nla & probably expensive if you do find one.

joe csuti · Mar 20, 2015

If it's any help I have wiring diag for 518h & 520h light bar which are both the same and are as follows along with terminal numbers & wire colors,this is only for light bar connections,I've never seen an actual internal wiring diagram of light bar.

1-air cleaner-brown
2-seat sw-red
3-acc volts-pink
4-hydro temp-orange
5-oil pressure-dark blue
6-pto-yellow
7-test sw-gray
8-start volts-dark green
9-netural sw-light green
10-parking brake-purple
11-cyl temp-white
12-ground-black

It's also noted on diag #4 & #11 not on all models,if one tractor a 520-8 this might account for 2 less lamps in light bar.The only thing I would differ with you on is my drawing shows test sw contacts N/O & are only closed in test position to provide 12v to all lamps at same time as all inputs to bar are +12v.

jeffcat · Mar 21, 2015

There are so many advanced tinkererere persons on this sight. That is an easy fix to your problem. Now.. many times in electronic items you can have dirt somewhere or a tiny bit of corrosion. Maybe a broken trace pattern in the copper foil pattern of the board. Also a floating ground will mess things up. Here is why. There are driver transistors on the board that power the bulbs. If one of them has shorted internaly then you are screwed. A floating ground can signal them to turn on cause you get a voltage potential where it should not be. This is why I think it is the case cause you have several lights on. Sounds as if you have a couple problems maybe? One time someone hooked the battery backwards etc,,, caZAP. There has got to be NOS stuff on fleabay or a good used one. Do you have another machine you can swap with? Just my thoughts. Jeffcat

jeffcat · Mar 21, 2015

Adding a note. Just Goolged wheel horse circuit board and a hole bunch of stuff came up. Go Google it. There are repos.

Calling all Wheel Horse experts! 416-8.

T.R.K.

Well-known Member

joe csuti

Well-known Member

gab

Well-known Member

T.R.K.

Well-known Member

joe csuti

Well-known Member

joe csuti

Well-known Member

jeffcat

Well-known Member

jeffcat

Well-known Member

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