Strange temperature issue

[Fozymandias]

Hi folks,

2001 JDM Forester, EJ205. About four weeks ago when I parked up after 30 mins normal driving, the temp gauge climbed up suddenly to about 3 quarters. I turned off the engine, turned the ignition straight back on and it was at it’s normal position straight away. Remained there and had been normal ever since.

This morning, happened again, pulled in the same place after 30 mins and off it went, same as before. Engine off, ignition on, normal position. I drove on 5 mins and parked up, turned off the engine but this time my fans stayed on.

My gauge has always had an intermittent issue where every now and then the needle doesn’t rise at all, I have to tap the dash to get it working. I was assuming that the first ‘spike’ was related but the fans staying on have me thinking it could be something else?

I’m not losing coolant, thermostat is 12 months old - changed pump, belt and thermostat last year (all OEM stuff) and I changed coolant 5 months back and haven’t gone near it since. Heaters blow hot air no problem.

I’ll plug it in to a diagnostic at the weekend and see what temp the ECU reads, if it stays within range then it seems to be something electrical. Car has two temp sensors one for the gauge and one for the ECU. Which one controls the fans?

Any other ideas?