Keep Having to replace the ignition switch on 318

[monster318]

Hello,
I have had my 318 w/ B43G for about a 3 years now, and so far I have just replaced my ignition switch for the 3rd time. The one that came on the tractor, had appeared to have gotten hot at the contacts and melted the plastic plug on the back of it. The second one failed while I was plowing over the winter at night, the lights on the tractor just all of a sudden shut off and after testing everything on the tractor I replaced ignition switch and the lights then worked.. Now the 3rd one has failed and its doing the same similar thing that the lights did to where I was mowing and all of sudden the front PTO shut off...and again I replaced the ignition switch and it fixed my problem.

I have always bought OEM John Deere replacement switches...I dont know whats going on...the only one I replaced that had visible damage to it was the first one that melted the plug..I verified in my service manual that I have everything wired correctly and the tractor is parked in my garage and only gets exposed to water if I am hosing it off or plowing in the snow so I dont think moisture is causing them to fail.

Anyone else had this problem?

 

[tcartwri]

They're running to much current through it You may need to put an aftermarket HD switch in it, or install relays for your high current hardware.

 

[Wnc3]

Are you running any non original accessories? If so run the power directly off the battery with an in line fuse. Or set up a relay as suggested above. The link below is dedicated to garden tractors and they helped me rebuild a 332 JD.


Weekend Freedom Machines

 

[monster318]

The only aftermarket accessory on it is 3 square halogen lights..two foreword facing, one rear facing. I removed the oem light harness from the 3 front hood lights... so power isnt being used there.

 

[beenthere]

Likely the switches are ok, just the extra load somewhere in the system that you need to track down. Sounds like you isolated the halogen lights.
If the present switch holds up, or hasn't been already compromised by the lights, then you may be good to go.

 

[jenkinsph]

I would install a good quality ignition switch from NAPA and a relay for the lights. Save yourself a lot of grief.

 

[N7943h]

I have found napa switches are not made the same and will not plug into your harness. Most of the time a melted wire or connection is due to a faulty connection that causes resistance and then heat. And good electrical connection at the switch should not melt anything. Too high of a currant for that wire should be protected by a fuse. I would replace the switch with a john deere part and at the same time splice in a new plug. You will be done with replacements and a happy camper down the road. I just had to do this to my 318.

 

[RandyT]

You don't say how big the halogen lights are, but assuming 55w driving lights. That is around 13-15 amp draw. The key switch should be rated for around 20 amp, but I don't know what else is drawing power. I would install a high amp relay or a separate high amp switch for the headlights.

 

[MikePA]

Great advice so far. Another idea, albeit expensive, would be to replace the halogen lights with LED lights, which offer the same, or more illumination, at a lower current draw.

 

[Kish318420]

Measure the PTO, look for to low of resistance, or a short, follow it back, checking all connections, check the ground on PTO and all other grounds, Also measure the current draw with the halos, as RandyT posted. Also N7943h as stated normally it will last, something else is causing it to draw to many amps and that what you got to find, Do you have the starter improvement kit installed for the 318? This is a must must because the starter solenoid (part of the onan p series engines can draw a lot) and melt things usually mounted down in front by starter.