Hey guys. I'm installing a new independent fan relay system in my 84 TA and was wondering what a good switched ignition source is. Any help is appreciated. Thanks!!

 

If you are looking for a switched source to power ONLY the coil of the relay , which draws microamps , then just use the large pink one that feeds the ignition coil . Now the relay's switched contacts , which are what will control the high current going to the fan motor itself , should get their power straight from the battery and NOT be drawing power from the same place the relay's coil . In this way you'll have +12v to the relays coil anytime the engine is running , but you won't be putting an excessive draw on the ignition coil's power feed circuit .

Does this make sense to you ?

 

It does. Power for the fans will come from the battery. I was going to use the source in the fuse box but my fuel pump relay is already using it.

 

I found at least two slots in my fuse box. Two of them are powering fan relays in the bay.

Probe each femal slot with a tester. One will be power "on" only. Just slide a spade connecter in that slot not touching any other and you have what your looking for and is really the only way to make a truly independent circuit from the rest of the cars system.

Here's a diagram of the circuit I use. There are two of them each using there own temp. controlled, adjustable, fan switch. Works perfect. Each switch only cost me $20.00,and they have been working for a few years now.

 

Just a little info. for anyone looking to power a fan. There is a box next to the battery and is mounted on the wall. Its called a battery "Junction Block" and is where fan power should always come from.

It is always VERY hot. You should unhook both the positive and negative side of the battery before touching it.

Just take off the nut on the post where the other wires attach and use a ring style connecter sliding it on,then reattach the nut .

Here's a photo of it.

 

That is what I"m using for primary power to the fans. I'm just looking for switched power for the relay itself. When the relay switches, power will come from the fans.

 

Wire for the electric choke ? Might be able to tap into it close to C100 and then run your switched power wherever it needs to go.

This is from an 84 Camaro,... but your C100 should be similar:






If your car originally had a functional cowl you might be able to tap into some of that wiring too.

 

Ozz1967 ,

When you said your getting power from the battery I figured you were using the "Block".
But just incase others don't know where or how dangerous the " block " can be a little info and photo could save someone from getting hurt.

If you want a truly independent circuit than you must probe the slots in the fuse box for what your looking for.
If you don't use the fuse box you will not have a "independent" circuit by tapping into another location/wire.

It does not matter what it says on the fuse box for the slot, as long as it has key "on" only power.

I guess you might already know this but the best tool I have found when looking for any 12v source is a Probe Test Light. So simple and fast and you can get them for a few bucks. = http://www.harborfreight.com/circuit-tester-30779.html

Side note = I place a 1amp inline mini fuse on the wire going to the fuse box from the relay just before the connection. I don't like the idea of any wire going to the box without fuse protection.

 

It shouldn't pull that much juice, can I use the same slot twice? Or should I use only one slot per powered item? I.e. Fuel pump relay and Fan relay.

 

Id still probe for a separate slot .That would be the way to go, but if you "absolutely" have to I would rather double up on a slot for the low amp coil side of the relays than cut into a existing wire in the bay.
As long as they are both simply powering the coil side of the relays you could run both wires together on a single spade connecter slid into the slot.

 

I found one, it was right in "front" of the other one I'm using for my fuel pump relay. I also found two "always hot" ports.

 

Really glad to hear you found one.

You could have an adjustable fan if you used the diagram I provided. I placed my fan controllers out where they could be seen but they can be hidden as well. (I painted mine black )