Mine runs from around 84 deg in cooler weather, to around 92 deg peak.
I'm no electrician, so the wiring & relays took me a bit of time; but it's not brain surgery.
Once I have a correct temp normally closed switch; mine will be great, as the default for the system if anything goes wrong with the switch is fans on.
When the switch opens, it releases an energized normally open relay, which then applies 12v through two 20amp fused normally closed relays.
Possibly would've been better going with a dedicated fan controller, but I can't find one that I'm prepared to pay for.