Swapped out fan circuit connector block with hazard light switch block.

These connectors are the same form factor, and whilst working in dim lighting I reconnected them incorrectly ...only about 3 years ago (and until now ). 

I was sometimes perplexed at why the radiator fan had never come on ... and although I hadn't clocked up huge miles; was musing other than an overheating issue what impact (s) this might have had on other things such as, for example fuel consumption, spark-plug appearance etc. (if any)

Any thoughts would be appreciated.

If the temp warning light in the cluster never came on then it's a non-issue.

Good. So where does the warning light get its signal from?

From this:



It monitors the coolant temp and turns on the fan at 103C, the temp light at 111C. Not surprising that your light hasn't come on. Unless the outside temp is very hot AND you stop for a few minutes the coolant temp usually won't get up to 111 when the fan doesn't come on at 103.

Great, thanks for explanation; you are one of the many 'good buggers' tirelessly keeping K-series bikes keeping on.