I want to know the easiest way to wire up some indicator lights so that I know which fan is running.

Could I run ignition positive to a light and then run a ground to the fan motor ground wire? Or are the fan motors always grounded?

I am looking for the safest way to wire up the indicator lights.

thanks

 

Hmmmm, I've often wondered about doing something like this myself. Though I've wanted to do it a bit differently - I wanted lights when my fan stopped working. Couldn't you just wire a light in series with your fan wiring? Just splice in a light? I mean, when there's juice going through the wire, meaning the fan is on, then there would be juice going through the light. No juice through the fan, no juice through the light; right?

Just my two cents Manny,
Steve

 

That's one way to wire it up.

 

Don't wire it in series, all that will happen is that the bulb will light but the fan won't turn. Tap into the blk/red wire of each fan relay with a 3M tap, put a little grease on to insulate it from water then run that wire to the center terminal of any 12 volt bulb and ground the other like any standard bulb wiring. Fan relay energizes and bulb lights. I would throw a small 1 amp fuse in each line as close to the relay as possible in the event of a short in the added wiring. I saw a tg locally where the guy used the "shift" lens in the light section of the dash. He used a green lens with silkscreened "fan on" letters. Really neat.

 

I am thinking about putting 2 LEDs in the gauge cluster right above the temp gauge.
I am always checking my coolant temp and oil pressure, those are the 2 most important gauges to me.

 

Very dooable! Cathode end of diode(led) goes to ground, anode goes to the relays like the bulb but use a 390 ohm 1/2 watt resistor in series. Different color for each fan, yeah I like it.

 

why not run a ignition feed to the lights, and then tap into the ground wire for the coolant temp sender

 

I think tapping to the fan wires at the relays is a better idea, that way if a relay fails you know the fan is not running when it's supposed to. And the 2 LEDs is the way to do it, they are not extremelly bright to become a nuisance.

 

That's what I did when I swapped an electric fan into the SC, except one fan=one LED. It lit up when the power was on, and faded out as the fan 'wound down' after power to the relay was cut. Also noticed at night, the LED would start to glow when driving about 50 mph....showing that the fan motor was turning fast enough to generate adequate current to light the LED.

Pete

 

I like that!