Relay switch seems to keep Failing

[Dave M7040]

They are not part of the relay as the relays are usually quite generic often used as relays for headlights or additional driving lights. I would start at the starter solenoid and follow the correct colored wire until you find something looking like a plug in connector. Local auto pats stores sell them for about $6. No need to go to the dealer.
Dave M7040

 

[LD1]

The diode wont effect weather the tractor will run or not. You can actually run without it, it just prevents other unwanted damage.

If I understand you correctly Dave, you are saying that repeated failure of the relays can be the diode?? But that shouldnt be the problem in this case, cause relays are good as far as we know at the moment.

 

[k0ua]

The diode could fail in the open mode or could fail in the shorted mode. If it failed shorted it would short out the relay coil and prevent the coil from energizing, and prevent the relay contacts from operating. Thus preventing the tractor from cranking.

James K0UA

 

[LD1]

Yea, I guess thats a possibility.

I am no expert, but most (if not all) diodes that I have had fail over the years, always failed open. So I guess I didnt even think about failing shorted.

 

[k0ua]

Yea, I guess thats a possibility.

I am no expert, but most (if not all) diodes that I have had fail over the years, always failed open. So I guess I didnt even think about failing shorted.

I have seen both failure modes. I have seen them burned open to the point of an air gap in the middle of them, and I have tested many shorted diodes. And I have seen them vaporized from lightning strikes where they do not exist any more. Just a black spot.:shocked:

 

[Dave M7040]

The initial post in this thread said ``the relay switch for starting and that worked for awhile but now it seems the switch is fried again.``
I know others had made the argument that the problem might not be the relay but I was just trying to inform people who were thinking of the original post of why repeated failures can happen.
Dave M7040

 

[Dave M7040]

Here are some photos showing the flyback diode and how it is incorporated into the wiring.
Dave M7040

 

[MotorSeven]

I have never heard of a flyback diode(that's what I love about TBN). That being said, would it not just fail completely and not on an intermittent basis?

First things first: Clean ALL CONNECTIONS on the battery, both neg & positive whether they look good or not. Clean the ground where it attaches to the frame. Load test the battery to rule it out(or in). Unless you do all of this first you might be chasing your tail.

 

[RandyT]

I have never heard of a flyback diode(that's what I love about TBN). That being said, would it not just fail completely and not on an intermittent basis?

First things first: Clean ALL CONNECTIONS on the battery, both neg & positive whether they look good or not. Clean the ground where it attaches to the frame. Load test the battery to rule it out(or in). Unless you do all of this first you might be chasing your tail.

The ones that we install on mowers with the kohler engines, and electric pto clutches, Kohler calls clamping diodes. Had problems with the electric clutch acting like a generator when shut off and blowing the ignition modules, and ECU's on the fuel injected engines.

 

[k0ua]

As an electro-curious child, I remember the first time I discovered the joy of taking a 9 volt battery and putting on directly on the AC plug (unplugged from the wall socket) of a portable radio and then removing the battery while holding my fingers across the plug. The resulting jolt was a BIG surprise and totally unexpected.

The portable radio of course had a small transformer inside as part of its power supply to allow it to run off of 120 Volts AC. The 9 volt battery made a nice electromagnetic field in the primary of that small transformer, and when I removed the battery that field instantly collapsed and turned back into an EMF and flowed out of the transformer and into my fingers.. WOWZA. that hurt!:shocked: Lets do it again!:cool2: If any of you would like to repeat that experiment, please do. Pictures if you can get someone to take them.!

My brother in law, one upped me though, he took a "cheater cord" which is just a cut off appliance electric cord with the raw ends bared. He plugged in the cord carefully into a 120 volt electric socket, and took the bare ends into a dark closet and closed the door. His goal was to "strike an arc" with the bare ends and be able to observe that arc in the dark closet.

Well he did just that, and of course there was a fireball of some substantial size. Apparently the fuse for the wall socket also powered the room lights, and the happy event was also done at night. He ran out of the closet bumping into walls, screaming at the top of his lungs to his mother that he had blinded himself with the initial arc. Since there was no light in the room and I am sure his night vision was somewhat diminished by the fuse blowing arc in the closet, I imagine it was sometime before he "saw the light" again. Not to mention his mother "busting his butt" for causing all the problem in the first place.

Anyway just killing some time here until the OP comes back and tells us what he has learned so far.

James K0UA