sure.

I made up an LED tester with an LED, and resistor. Before I wired it up, I tested the socket of the relay to see which one of the contacts was powered. The relay turns the fans on. One side is always hot. At least on my car. Other cars may need the key on? I hooked the positive side thru the resistor to the relay (the switched side) as shown. The negative side I just hooked to the nearest screw with a crimp on terminal. and soldered the little red wire to the other side. I should have put a small fuse inline near the existing fuse box. If you are not really comfortable with electronics, I don't recommend doing this yourself, bad things could happen. Anyway, on my car, the fans are turned on as soon as you turn the AC, so its a quick way of testing the LED...


Heres a pic of the LED tester. I make these all the time...

https://home.woh.rr.com/slurp812/fan_on_5.jpg

The black side is hooked to ground, and the resistor side is hooked to whatever it is you want to test/indicate. In this case, its the fan relay. Notice the Negative side is the bigger of the 2 pieces of metal inside the LED. Also the metal thing above it is a holder like I used in the car. Just makes it look neat.

I hope this doesn't sound too confusing.....

cool ,,what resistor is that :thumbup:

I too would like to know the value of that resistor. It appears to be gold-red-black-brown (1k) but could be gold-red-green-brown (1m).

If you have a supply of these available, a common 12v phone charger or other 12v adapter with an LED could save some time, depending on where/how you want to mount it. I've got an abundance of these and intend to use them for such things as a fan indicator. Just crack it open, hack wires on to it, and maybe extend the LED away from it.

It is a 1000 ohm resistor. So yea its a 1k. Most LED's are usually 20 milliamps max, and the 1k should make it a bit less than that, close enough. :D

Slurp, while we're meandering... I have an 04 Si. Have you considered cutting some of the back bumper up higher while also smoothing out underneath? Talk about a big air brake area! I was thinking of cutting out along the indented lower area. I'm sure we could get 2-3 mpg on smoothing out the whole bottom and raising the rear, etc., etc. I also think removing the rear "wing" would help, might look funny, though.

thanks :thumbup:

removing the lower part of the rear bumper will definitely help, but i am not so sure of the duckbill "wing" on the hatch. it may have properties of a vortex generator.

For the indicator I used for my TCC indicator I got a green 12V led from radio shack. It was only a couple bucks but you don't have to worry about soldering in a resistor or anything and it's not so bright that it will ever bother you during driving. The only downside to it is if you mount it in a place that isn't shaded from the sun you can't see it come on in the day.

FYI:
If you don't want to mess with connecting your own resisters into a circuit, for just a little more money (than the cost of buying bulk resisters and LEDs and connecting them yourself) you can get a LED module already setup for 12v car systems. For example https://www.superbrightleds.com (a place I buy most of my car LED modules from, due to the quality and price of many of their LED modules) sells a 12v LED module (in your choice of colors) for $1.99-$2.99/each (depending upon color of LED). And their shipping (via US post) is only $5/order, as long as your order is under $100 (and for larger orders, shipping seems to start at only $10/order).

https://www.superbrightleds.com/store.../led_wired.jpg

https://www.superbrightleds.com/specs/wiredLED.htm


BTW:
I've personally been thinking of using that exact module mentioned (I've already bought a few in different colors) as indicator lights on my dash (I just haven't gotten around to wiring them in yet).

My personal thoughts were to wire up a green, a yellow, and a red LED (in a "traffic light" pattern?) on the (side of the) dash. I could then hook up the green to the FI (so I can get a rough idea of fuel use, including a clear sign of DFCO), hook the yellow up to the radiator fan circuit (so I can see when the fan is on, just like the OP is doing), and hook the red up to the brake light circuit (so I can get a clear idea when I've pressed the pedal enough to turn on the brake lights). Oh yeah, I was thinking of wiring the common ground (for all these LED modules) up to a small switch (and likely also a small fuse), before hooking them up to ground, so that I could easily turn on/off these indicator lights when I wanted to (so I'm not forced to see these lights at all times if/when I don't want to). Of course, that's the idea, and I haven't yet gotten around to actually wiring things up that way (i.e. it's on my "to do eventually" list)...

I don't want to start cutting the body panels just yet. :eek: I want to be able to put the car back like it was. I was thinking about something with the wing area in the back, not sure what tho. Oh and Draco you have some good ideas. As always, if I do anything it will be posted here first!