What Causes Key Switch Failure?

[dobro]

Pretty bizarre to have not used the oem connectors which are PLENTY big enough for the current application.
Means you have removed any possibility of a plug n play solution if ever needed down the road and now have a non standard main harness - sorry, would not have been my choice ....

Well, that's human nature: To screw something up repeatedly for 7 months out of ignorance and vanity then, when unavoidably confronted with the evidence of having done so, to screw it up even worse as a last stand effort to validate oneself.

 

[DEcosse]

That's a bit harsh on yourself - but I might be inclined to recommend a different shop, at least where electrical work is concerned

 

[TURBO200R4]

what causes key switch failure? was your question
the current passing through the connectors and switch is more (creates heat) that the switch/connectors can handle. that is why the early rockets with two lights went with the eastern beaver or installed relays to take the current load out of the switch. some have went with daymaker lights to have better lights and reduce current load.
i have not spent any time looking at the r3t wiring and do not know how to advice u but if it was mine i would look into a good head light. hth

 

[DEcosse]

.. the current passing through the connectors and switch is more (creates heat) that the switch/connectors can handle. ...

I would agree with the switch being unable to handle it (on the pre-Roadsters anyway) but respectfully, not on the connectors - assuming the connectors have not been compromised*.
The Touring only has one headlight, so you're knocking 5 off vs the load on the early R3's. NOte that there are no examples (I could find) of Touring model key-switch failures.
*This one - and one other here on the site - have had issues with connector position 1 terminal (which is the supply current for headlight, starter solenoid and ignition circuit current) but I would have to believe this was due to a loose-fitting female terminal - a loose fit creates local heat and then it burns. This is not exactly a prevalent problem on Tourings - those Sumitomo connectors are excellent quality & if assembled correctly should definitely not fail.
Even something like sticking a test probe into the female is enough to compromise it. Not saying that is what happened here, but I honestly don't believe this is a widespread issue (like the early bike key-switch failure)
You could say - ah but the later ones have the Sumitomo connector and that is the new 'weak point' in the chain vs the early; however the early models changed to that connector in 2008 - and on those the weak point remained at the key-switch, not the connector.

But absolutely, if you reduce the load through that circuit, you certainly reduce the likelihood of failure, wherever it might want to occur.
One extremely easy/low cost way to reduce the load through that circuit (on a Touring) is to remove the green wire from the Fuel Pump relay and replace it with a fused wire from the battery.