Hey,
I wired my fan to a relay/toggle.
When I first wired them to drive the 20 miles after the engine swap, I used a toggle and nothing else. Worked great.

Today I bought a 40 amp 4 pin relay and wired it like normal.
30- 25 amp fused from battery
86- Toggle
85- Ground
87- power to fan.
I used 12 gauge on the relay power and ground(30 & 85), 16 gauge to trigger the relay from the toggle(86), and 12 gauge to power the fan (87).
Now when I turn the switch on, it keeps popping the fuse. It's a 25 amp blade style. I went back to the 30amp toggle with no relay, and it works just fine. I checked all the grounds and all seemed well. The only thing I can think of is that the guy gave me a relay from a fog light kit. I can't see that being the issue rated at 40 amps. I can't figure out why the fuse keeps popping from the main power to pin 30.
It's a 16" Hayden fan rated at 16.5 amp draw.

Here are the specs.

• Thin Line
• 16" Diameter
• Black
• Mount Area: 15-3/4 X 16-3/4 Inch
• Thickness: 4-1/4 Inch
• Free Airflow (CFM): 1,400
• Airflow Through Radiator (CFM): 1,150
• Amp Draw: 16.5

Anybody have a suggestion about the blowing fuses?

Could be as simple as a bad relay?
Thanks for looking
Turk

the relay might have a built in clamp diode across the relay coil-that will act as a short if connected backwards,will be a short both ways if diode damaged by reverse connection.

I wouldn't think it is. I can get it to run for a few seconds before it will actually blow with the relay wired up.

bad relay. works fine now.
thanks