[D18]

I’ve got a fan issue where the fans don’t seem to kick on by themselves. I can however use the A/C button to make the fans kick on, so I do know they work. I’ve had this issue for two summers now and have been using the A/C button to turn the fans on and off as needed. I have an aftermarket water temp gauge that I use to accurately read the temps. The dash gauge still works too, and although it’s harder to read exact temps on it, it does look like they are always in alignment.

Around the time I noticed the fans had stopped working, the A/C also stopped working. Investigation showed that my Mishimoto oil cooler’s stainless steel lines had rubbed a hole in the A/C hard line releasing all the refrigerant. I had assumed that the fans were somehow related to this A/C issue, but I finally fixed the A/C this month by swapping out the hardlines with new OEM ones and getting it recharged at the dealership. I still have my fan issue though, and with the A/C working again, I don’t want to be constantly flicking the A/C on and off just to turn the fans on/off. I’ve looked at all the fuses and tried swapping relays around, but it hasn’t made a difference.

Does anyone know of a secondary sensor that the fans use to measure the coolant temp? And do you know of an easy way to check if it’s not functioning properly? Or even better have you experienced this issue before and do you know how to fix it?

My car is a 2013 Scion FRS. I’ve had it since new in June 2012. Its been supercharged with the Jackson Racing kit since 2018. Radiator has been upgraded to the Mishimoto, and I’ve also swapped out the thermostat for the Mishimoto racing one. I mostly drive this car for weekend cruises or on the race track, so it doesn’t get a lot of km’s. I’m only just getting to 60k km’s.