Im running a taurus 2-speed fan. Have it wired up to a 210on-200off temp switch for low speed. High speed is controlled manually via my on(auto)-off-on(hi) switch. Both speeds have independent 80A relays as well as independent circuit breakers and everything is wired using 10ga wire. Never had a problem in 110F+ heat, at idle, with A/C on full blast....the low setting never let the temp go over 210 and this was verified via my Scanguage II. If you have any questions, pm me.