Pully vs. Electric fan

My fan draws something in the neighborhood of 10 amps. Th only time it comes on is when I'm sitting in traffic.

 

I plan to run it on a relay. Obviously the light is only going to show weather the fan is getting power or not, and not weather it is actually running, which I know is what you are getting at. But I have a temp gauge to let me know if something is wrong. I usually glance at my temp and oil pressure gauges periodically, or whenever I stop at a red light, just out of habit. But I understand some may not do this until it's too late.

I am going to try what I was saying earlier with a 2 speed fan and see if the coil not in use is generating any power. If it is, I will use that to power the light. I will let you know how that works. I really can't think of anyway besides that to tell if the fan is running, unless you rig up some kind of magnetic pick up system on the fan (I keep getting this picture in my head of one of those cheapo electric bicycle speedometers that has the magnetic pick up on the wheel)

My '72 just has the stock alternator on it, the car is a daily driver and I haven't had a problem yet running my stereo, headlights and fan at the same time, even sitting in traffic. The lights do dim when the turn signals flash, but that's about it. The car maintains 14 volts no problem and never had a problem with the battery going dead. The battery cables on it actually look thicker then my dad's '95 Mustang..

 

The late 80s early 90s Taurus 2 speed fan is a great fan. They are every where at the junk yard and flow massive amounts of air. My friend retro-fits every old car he has with them. Buys a temp activated switch and hooks it up. Very reliable. I think it cost less than 30$ total.

 

i've heard alot about taurus fans being good