My 2005 has a v2 with fan settings that worked correctly for a couple years, but recently it's been acting oddly. The fans use the OEM wiring and relay, and the fan switch is a Mishimoto 80C (176F) switch, which I wouldn't think mattered if the AEM is sending the signal. Even with the AEM 'On Above' at 190F and 'Off Below' at 180F, the fans will switch on between 178F to 180F and switch off around 174-175F.

I've got nearly identical settings to "E4RTH WORM JIM" https://www.s2ki.com/forums/s2000-fo...-625114/page3/, and from my experience (plus recent searching around to verify) those settings are considered the standard. As I mentioned earlier, I had the settings for a couple years and was able to manually control the fans with the AEM at my specific temp settings without issue. Only recently it seems to have spontaneously 'chosen' to use the factory switch settings.

Any thoughts as to why this is occurring?

 

I'm curious 'cuz I thought the radiator fans before 2006 were strictly controlled by the thermal-mechanical radiator fan switch in the bottom of the radiator or turning the AC on and the ECU had nothing to to with it. 2006 fans are controlled by the ECU and that was a change when the car went DBW. 176°F seems a it "cool" for the fans to be running.

Be interested what you find.

-- Chuck

 

We'll that's interesting then. So longer version, the radiator is second hand and I used the originally included switch that was in there both before and after the AEM install. It was only after I had cleaned up the wiring to the switch that it started exhibiting the aforementioned issues, though only sporadically. That's what led me to the replacement switch with a Mishimoto instead of an OEM. It's possible the older switch was damaged and my messing with the wiring let it work correctly. Quick test when I can find time between weather, work and family will be to disconnect the switch and see what happens. Will report back in the coming days.

 

Confirmed that unplugging the fan switch connector allowed the V2 to control the temp limits on the fans again. The older switch must have had a short that caused the intermittent control. Consider this solved and closed.