3.8 tarus fan install electrical issue

[5150coupe]

i installed a ford taurus fan into my 89 5.0 and i'm having trouble with wiring. i melted the 75 amp relay/fan controller and so i went directly from the fan to a 40 amp fuse to a 50 amp toggle switch to the battery, so it was manually controlled. the 50 amp toggle switch melted. the only other wiring is a diode between the positive and negative to protect the fan motor. it always felt hot around the switch like there is resistence, but there shouldn't be with a 50 amp toggle switch. i'm running the fan on the high setting. with the fan running it only felt hot around the toggle switch. can anyone explain why the 50 amp toggle would melt before the 40 amp fuse and why the fan would melt anything that high in amperage?

note: i also upgraded to a 150 amp alternator to support the fan and future electric water pump.

[rwhite65]

I would be suspicious of the switch, more specifically where you bought it from. Those fans do have a decent draw on them though.

[ustahava67]

This fan will pull over 100 amps at start up. I'm running delta current controls fan controller. It automatically controls the fan speed using a temp sensor.

[bmxmon]

What gauge wiring are you running? Here is a chart which shows what gauge you need for your expected amp draw and length.
Wire Gauge Tables

[ustahava67]

I'm running 10 gauge wire to the controller. The DC controls unit slowly ramps the fan up to avoid the initial amperage spike.