Fan wiring questions

[domstriker]

Fan wiring questions-Relay or no Relay

My Pro comp tranny fan is arriving tomorrow. I just got back from radio shack with supplies.

I got 12 gauge wire with an inline blade fuse holder. My switch is rated at 20 amps. Fan is 4.5 amps.

I wasn't planning on running the wiring through a relay. After reading a bunch of other forums, most of them recommend using a relay. Is it necessary?

Also, what amp fuse should I use? I'm guessing under 20 amps but more than the amperage the fan requires?

 

[domstriker]

bump

 

[djbrand1]

I would run a relay. Simplifies the wiring coming into the switch, and you dont have to worry about the high current going through the switch. Fuse should be 10 amps. I think you can get a 5 amp fuse, but that might blow with the fan turning on and off. I was looking at doing a thermo switch when I put my fan on.

 

[domstriker]

I would run a relay. Simplifies the wiring coming into the switch, and you dont have to worry about the high current going through the switch. Fuse should be 10 amps. I think you can get a 5 amp fuse, but that might blow with the fan turning on and off. I was looking at doing a thermo switch when I put my fan on.

Thanks. I have a scangauge and after my milkshake, I'm always monitoring my ATF temp. I would rather turn it on and off when needed as opposed to using a termo switch.

Do you think that 12 gauge wire is thick enough to run from the fan to the relay? Is it okay to use 12 gauge from the relay to the switch?

 

[djbrand1]

12 gauge should be fine for relay to switch, you could probably go smaller if needed. That is just supplying a very low voltage signal to tell the relay to open or close. Power to fan should be fine with 12 gauge too, go 10 if you have any doubts.