Aux Fan

[carpeonnel]

I was a yard sale the other day and picked up this fan that appears to have been from a transmission cooler set up. Picked it up for $4 and I figure I could use it as an aux fan for my K5. It's a simple 2 wire setup (red & black) and I was wondering if anybody else had done this and if you think I would need some kind of relay

 

[vortec]

yeah, i'd run a relay for it. could save you from burning up switches for one thing.

also, i'd want its circuit to only be hot in run. otherwise, you might forget to switch it off and kill you battery. i've almost done that with my offroad lights a few times.

 

[carpeonnel]

Any certain relay you think would be best?

 

[vortec]

i run a 30 amp spst (single pole, single throw) relay for my offroad lights on both trucks. one is bosch, the other is a cheapo from radio shack. both have done a good job for years. the fan might need something a little more robust (60 amp?). judge it by the motor's spec, of course.

a side note, i use inline fuses in both the circuit that operates the relay and the one that carries power to the lights. that way, i don't smoke a relay, wire or switch, if there's a problem.

 

[carpeonnel]

I guess I'll probably go with a 60 amp I guess, cuz there's no identifying markings on the fan at all

 

[vortec]

i'd probably install it and backprobe it while running to find out what kind of amps it's pulling, particularly when it first starts up (the fan, not the truck), then select the fuse accordingly. you definitely don't want to use too much fuse or you'll start frying wires. that's a hassle at best, and a potential a fire hazard.

 

[83ZZ502_Jimmy]

For that size fan, a 30A relay will be plenty.

I use them all the time for fans.

John