Toro Timecutter SS5000 - starter keeps running with key off

[Auto Doc's]

The wiring diagram shows a diode in the starter solenoid harness. I suspect the diode is bad/blown out and allowing current to flow the wrong direction. Jump starting or a continuous low battery will stress and fail system diodes.

 

[Grunkle]

I only had to jump it once, but replaced the battery right away. I didn't see the diode in the diagram.

 

[Auto Doc's]

I only had to jump it once, but replaced the battery right away. I didn't see the diode in the diagram.

I misread star tech's reply. He is actually suggesting putting a diode in and indicated by the partial diagram he showed later. This would eliminate the starter having unwanted voltage from the controller that is keeping the starter solenoid powered up.

The way I am understanding your problem is that the starter is being energized into crank mode at all times.

 

[Grunkle]

You are understanding the problem correctly. Once the ignition switch is turned to "start", the starter remains energized even when ignition is moved to the "off" position, until I disconnect the ground.
What sort of diode should I install, and where do I get one? I have rewired entire vehicles and homes, but never dealt with a diode...

 

[Auto Doc's]

Hi Grunkle,

Do you have a simple test light and a multimeter. If not consider getting them, otherwise everyone is guessing. Some issues like this are just not going to be simple without some testing and good notes, so you don't get confused.

Go all the way back to the original diagram (that is your roadmap) that Startech provided you and verify every wire is exactly connected to the correct pin location. Anyone could have been blindly swapping wire pins around before you got this machine. I have seen this kind of thing happen before. (People who mean well, do not always do well).

The whole issue seems to be pointing at the brake controller "brain box" of the circuit. It could likely have a diode or a switching micro-solenoid inside of it that is bad. (Don't condemn the part until all harness and connection have been confirmed good)

Was it a used brake controller that you installed initially?

By placing a rectifier diode in the start wire right where it goes into the controller (pin #2), it would prevent voltage feedback from the brake controller to the start solenoid. Note the direction of the arrow on the diode. It has to be placed as indicated in the diagram portion provided by Startech

A rectifier diode is a 1-way electronic "door" that will only allow positive electron "power" to flow in one direction and stop it if it tries to travel backwards. Many people refer to them as a "gate".

A rectifier diode can be purchased at Mouser.com or on Ebay. The only mystery is what Wattage would it require.

Basic rider mower cranking/power circuit has 350A capacity battery at 12.6V with a 14.7V charging average

Maybe we have an electronics savvy member who can chime in here? Maybe Startech can elaborate further.

 

[Grunkle]

The brake controller had malfunctioned, in that the brake wasn't releasing when the steering arms were moved from the "park" position. (sometimes they would, sometimes not)
I purchased a new (not reman) brake controller online specifically using the info from the mower. After installing the new controller, the brake was releasing properly, but then the problem of the starter not disengaging appeared.
I had thought since the mower sat outside last winter that the ignition switch may have gotten rain water in it and was malfunctioning, so I replaced it as well, again using specifics from the mower and not just getting a generic part.
I can't say how much I truly appreciate the help from this forum! You have all been so helpful!
I have used multimeters and test lights most of my life, and am very familiar with 12 volt up to 240 volt wiring. At least enough to rewire many trailers, trucks, and a couple homes and shops. (background as a farmer, mechanic, fleet mechanic, building inspection, home remodeler) But never got into messing with stereos or anything that used diodes.
I can fix nearly anything, given my back holds up. (too many surgeries to list) So installing a diode in the circuit is no problem. I prefer to solder and shrink tube rather than just crappy crimp connections. Do it once, do it right.
If I know what part to get, I'm happy to install it, and report back on the progress. Hey, who knows who else out there can benefit from all this fun?

 

[Auto Doc's]

Hi Grunkle,

Sounds like you have been around long enough to know that "new" does not always mean good.

A simple inline rectifier diode should do the trick. Typical V-twin engines have them in the coil kill wire harness if you have any old V-twin core engines laying around. Maybe you can borrow a diode out of a scrap harness for testing purposes. The diode should have resistance in one direction but not the other.

I also noticed on the full diagram that it is not showing the coil kill wire diodes and they usually do. They may be contained in the controller module.

 

[Grunkle]

I looked on Mouser.com, and got really confused. So I went to Oreillys auto parts website and found a "Littlefuse 1 amp mini diode" that would plug into a fuse holder I could install inline. Would that work, or is that high enough ampage?

 

[Auto Doc's]

I do not know if it would work, but worth a try. Maybe an inline automotive A/C clutch diode would be more effective.

 

[Grunkle]

Didn't see a A/C clutch diode, but see a 2-4 amp alternator diode you install inline. Think that would be worth a try?