PDA

View Full Version : Another electric fan wiring thread (with relays!)

Matej
08-31-2010, 03:19 AM
Good evening.
First of all, I apologize for making another one of these threads. I promise I only did so after I had no luck finding one for specifically what I want and that was also dumbed down enough at the same time.

I decided that I refuse to have my fan wired to a switch any longer. I want it turn on and stay on whenever I turn my key to ON in the ignition (or ACC, it does not matter really), and turn off when I turn the key to OFF. After searching around, I found out that to do so I will need a relay, fuse & fuse holder, and of course some wires and connectors. The problem is, I do not know much about relays or any such trickery.

On Ebay I came across this kit. I like how it already has everything and would save me most of the wiring work, and even includes the fuse holder and fuse.
12V ELECTRIC FAN RADIATOR WIRE WIRING HARNESS RELAY*iB : eBay Motors (item 300350168299 end time Sep-17-10 08:36:19 PDT) (http://cgi.ebay.com/ebaymotors/12V-ELECTRIC-FAN-RADIATOR-WIRE-WIRING-HARNESS-RELAY-iB-_W0QQcmdZViewItemQQhashZitem45ee43dcebQQitemZ30035 0168299QQptZLHQ5fDefaultDomainQ5f100)

Here is where my questions start.
1. In the kit, there is a switch connected to the relay. If I wanted the fan to come on when the key is turned, would I just cut off the switch and connect the wires to a source such as ignition or fuel pump?
2. If the answer to #1 is yes, this is a follow-up question. I see there are three wires going to the switch. Are two of them power, and one a ground to make the button light up? Would I connect the two power wires into the source and cap off the ground?
3. Does it matter in what order the power source wires are connected to a relay? As in, which way the current flows through the relay in order for it to do its job?
4. What would be a good source to tap the relay into? I see most people mention ignition and ACC. If there is anything in the intake side fusebox I could use for it to come on when I turn the key, that is where I would prefer to run it.
5. This is probably too much to ask, but if anyone could tell me where to find which wire for the sources, and possibly even the color of the wires to really dumb it down for me and anyone else who could use the help, that would be perfect. And pictures work wonders. :)


I am sure I will have plenty more questions as I try to tinker with this.
Thank you for any help or information.
zylvia213
08-31-2010, 01:24 PM
Not the set up that you are looking for but just thought I share this with you.

Check this link out... thats how I have my fans hooked up. I got a relay for each fan and turns on at a certain temp.

How To Properly Install An Electric Fan (http://www.aaroncake.net/rx-7/efaninstall.htm)
Matej
08-31-2010, 02:03 PM
Are the posts on the relays numbered, and are they always the same?
If so, would 85 and 86 be the ones that go to the ignition source?
chituntang
08-31-2010, 04:00 PM
For what you wanted to do, you do not really need a relay. Wire the fan into the stock e fan wiring, then remove the fan relay and jump the two large wires. Remember there are 4 wires from the stock fan plug, 2 power and 2 ground, and there are 2 relays to drive the 2 settings.

Remember what a relay is for: using a smaller current to trigger a bigger current. When you put the key into the ignition cylinder and turn it into the on position, you already trigger the relays to power up the car, which includes the power for the e fan.
Matej
08-31-2010, 06:00 PM
Already tried that way actually, however, the wiring in my car is kind of goofy, and it did not work. I believe the A/C fan wiring is not getting power.
Also, I read that it is not a good idea to run a bigger aftermarket fan on the stock e-fan wiring, so I would rather have separate wiring for the fans, to prevent any further electrical issues.
Matej
09-01-2010, 02:37 AM
Another question. I am still a newbie to relays.
To power a relay, does just one of the wires (86) have to be spliced into a 'hot' wire, while the other (85) would go to a ground?
Or should both 85 and 86 be wired into the 'hot' wire as a part of its circuit?


Also, could I use this OEM fan relay for this purpose? That way I could still have it neatly in the fusebox.
#1 would go to a 'hot' wire, #2 would go to a ground, #3 would go to the positive wire on the fan, #5 would go to the positive battery terminal (with a fuse in the wiring), and the black wire from the fan would go to a ground.
Please correct me if that would not work.
http://www.matejblahut.com/photo/auto/part/acfanrelay.jpg
Thank you.
Options13
09-01-2010, 04:53 AM
this would be nice to know, cuz i am tired of using a switch, lol
g6civcx
09-01-2010, 07:29 AM
To properly answer all of your questions, I need to know the following information:

1) What brand of electric fan(s) are you using?
2) What is the maximum load the fan is expected to pull?
3) How many amps should the fuse(s) be for the fan?

Depending on what fan you're using (OEM or aftermarket), you can find the fuse size by looking at OEM fuse sizes in the FSM or by talking to the manufacturer.

Let me know if you're stuck and I'll try to help you.

I also need to know what car you're working with. S13? S14?

My experience says that constant on is not as good as using a thermoswitch. Why do you want constant on?
VNG704
09-01-2010, 08:01 AM
You can use that oem relay. If you followed that link zylvia213 gave you, you don't need to have it powered by ignition. Your thermostat switch won't turn the fan on if it doesn't hit the set temp (190ish degrees F)

Oh, and you have 5 and 3 confused. 5 goes to fan, 3 to power/spliced into 1, 2 (thermo switch in) to ground, and 1 (fuse in, iirc I used 20A fuses) to power. It's all in that link. I think that is the exact link I used when I was doing mine. Just a heads up, don't use small gauge wires.
Matej
09-01-2010, 08:03 PM
To properly answer all of your questions, I need to know the following information:

1) What brand of electric fan(s) are you using?
2) What is the maximum load the fan is expected to pull?
3) How many amps should the fuse(s) be for the fan?

Depending on what fan you're using (OEM or aftermarket), you can find the fuse size by looking at OEM fuse sizes in the FSM or by talking to the manufacturer.

Let me know if you're stuck and I'll try to help you.

I also need to know what car you're working with. S13? S14?

My experience says that constant on is not as good as using a thermoswitch. Why do you want constant on?
Thank you for taking the time to help me out with this.

The fan is a generic aftermarket 14" slim fan. It should pull 1840cfm and draw 13.20 amps. The car is an S13, 93 fastback to be specific.

Constant on is just a personal preference. I would like to have it stay on just like a clutch fan would. Is constant on not as good because it wears out the fan quicker, or are there other drawbacks?
VNG704
09-02-2010, 07:04 AM
or are there other drawbacks?possibly electrical drainage and/or the components may get too hot and melt/burn.
codyace
09-02-2010, 07:33 AM
Constant on is just a personal preference. I would like to have it stay on just like a clutch fan would. Is constant on not as good because it wears out the fan quicker, or are there other drawbacks?

With it wired correctly and with a relay, no you shouldn't have any issues
g6civcx
09-02-2010, 01:32 PM
draw 13.20 amps

Check with the instructions to see if there is a recommended fuse size.
Matej
09-02-2010, 07:32 PM
Unfortunately there are no instructions. I was just going to use a 30amp fuse, since that seems to be the most common one that I see people use for fans.
Smurf_240SX
09-02-2010, 07:57 PM
subscribed for when I get home.
g6civcx
09-04-2010, 01:03 AM
The size of the fuse determines the size of the power wires in the circuit. I'll come back to it if you ever figure out the actual size recommended by the manufacturer.

1. Never piggyback more current than what the circuit was originally designed to do. You can tap an existing circuit to power a relay because a relay pulls a very small amount of current. You can pull any wire that has ignition power as the source to trigger your relay.

2. If you're running constant-on there is no switch so your question is moot.

3. As long as 85/86 gets current and ground, it doesn't matter which is which.

4. I don't recommend messing with the relay box. There isn't a really good option on the Nissan. If you twisted my arm I would probably tap the ignition relay trigger wire in the relay box.

5. I would tap the ignition switch to power the relay.


One of 85/86 goes to the ignition power wire and the other one of 85/86 goes to ground.


The blue relay you described would work the way you described. If using a universal relay, power should always be 30 and the fan be 87.

Your wiring should be like this for an aftermarket relay:


85 (or 86) - pull ignition power from anywhere
86 (or 85) - ground
30 - thick wire straight from battery with fuse
87 - fan

Also don't forget to ground the fan.


That's your entire fan circuit.
upsdude
09-04-2010, 01:39 AM
i just used the a/c fan harness for my efans. so far so good, drove up the cajon pass on a 100 degree day with the a/c on full blast w/no problems.
shadowcorp
09-04-2010, 12:16 PM
I made this thread with handy printable images so hopefully that helps if you haven't already figured it out

http://zilvia.net/f/tech-talk/341127-fan-wiring-simplified.html