Altima Fan Wiring Question

[Ian]

First off, yes I did search.

I want to wire my fans to be on all the time with ignition at high power. I understand that to do this, i wire up both sets of wires on each fan instead of one (low power).

I also read that to do this, I can wire the fans up to the Fuel Pump Relay, and just add a slightly higher fuse (15A instead of 10A) and that is it.

Is this safe to do? I want to know before I do it and end up blowing a fuel pump fuse in the middle of nowhere.

Thanks,
Ian

[orion::S14]

If you're using the fuel pump lead to trip the relay ONLY, that should be fine...and re-wire the fuel pump at the same time, if you haven't already - You don't need even that little extra bit of current draw taking away from the pump.

Assuming this is S14...there are 2 relays for the fan, both need to be switched to be hot with the ignition (of fuel pump feed) to get high speed...so permanantly ground both negative sides of the relay, and use the fuel pump + to switch them on.

THEN add 2 MORE relays for the second fan, wired in the same fashion.

Easy.

- Brian

[420sx]

dont need no relays. wire them together then split the power in 2 and use 2 fuses on acc a 20 and 15 amp in the kicker panel fuse box on the driver side. so 35 amp total. there u go on with ignition and cools like a mofo. ground to the battery.

[wootwoot]

Orion's idea is dialed. Do that and just use some inline fuses and you are done. Not ghetto at all.

[420sx]

the way i posted it will never disconnect or fail. if it blows a fuse there will be a back up haha. so ur will never be without a fan on

[MELLO*SOS]

^^ These are good ideas.

I don't know why my altima efans are different, but here's how they work for me:

+12v blue, (-12v black & -12v green) == low speed

+12v yellow, (-12v black & -12v green) == high speed

(+12v blue & +12v yellow), (-12v black & -12v green) == fans don't spin at all!

From the wiring schematics I've seen there are two pairs, yellow/green and blue/black. Depending on which wire you send power to (blue or yellow) switches the speed, so long as the others are grounded (see above)

GL

[Ian]

orion, can you explain this to me a little better? I am retarded and do not understand exactly what you mean...


to be honest, i know jack shit about wiring, so i dont even fully understand what a relay is (i think it's a type of automatic switch?)

[wootwoot]

a relay is something that uses a different voltate to signal an amperage. In this case as Orion planned you need the fuel pump to relay your fans. This means that whenever your fans need to be powered, your fuel pump must tell them to. Your fuel pump turns on the second your key is inserted so that way it builds pressure so your engine can run safely. So This means that the circuit would be alerted whenever your pump is turned on. Relays opperate whenever a voltate from something else is sent to the relay. They act as an open circuit until something else tells them to. I hope that makes sense because I aint sober.

[Ian]

so when voltage goes through the relay, it effectively "flips the switch"




so where do i find this fuel pump relay?

i assume i run a wire from the fuel pump relay to the fans (spliced so both powers go to the fuel pump relay) and then ground the fans to whatever chassis bolt is near.


to clarify, i'm wiring this fan from scratch. The wires are all cut on the fans and i have no AC fan or anything, no ac system, no residual wires that i can recognize at this point. My engine bay is pretty barren...

[wootwoot]

Yes, the relay basically flips the switch. The full voltage runs to the relay, and whenver the relay is "told to" release the full voltage it does through how ever you wire this. A standard bosch relay works fine. I recommend for fans an inline fuse, a relay, and a controller but your controller is simply the fuel pump which works fine for how you want it to work.


http://www.partsexpress.com/pe/showd...number=330-070

Thats what you want. One for each ground/power you are going to use. So in Altima fans you would want 4 of those suckers which is ghey and clustered but that is the proper way to do it.

[Replicant_S14]

Originally Posted by mainevent212

so when voltage goes through the relay, it effectively "flips the switch"

Right. In your case, you'll use the fuel pump relay to "flip the switch" on an additional relay that powers the fan.

How relays work

i assume i run a wire from the fuel pump relay to the fans (spliced so both powers go to the fuel pump relay) and then ground the fans to whatever chassis bolt is near.

oh man.....I smell wires burning.

[Ian]

gah...i hate when people do that^


you're like the computer tech guy that gets frustrated at the office workers when they dont know how to do something lol

I know nothing about wires...sorry.

at least i'm not posting "omg0rzz i fri3d my motor because i wired my electirk fanz wr0ng!~!!!11one"


thanks for the link about how relays work though. I'm gonna make sure i do this properly.


(i want fans on all the time because most of the time, my car isnt moving in a straight enough direction to get natural airflow through the radiator)

[Ian]

Ok, so after reading the HSW page on relays, i think i get it.

I use a relay on each positive wire on the fan, connecting the electromagnet part to the fuel pump. This will allow the fuel pump to send a tiny bit of electricity to my relay, telling my fans to turn on. I then hardwire the relay to a power source (i assume i can just wire it straight to the battery) and ground it at a common engine ground.

right?


EDIT

i drew a pretty picture

[420sx]

heres mine. my paint skills suck haha

[Replicant_S14]

Originally Posted by mainevent212

Ok, so after reading the HSW page on relays, i think i get it.

*snip*

right?

Yeah. Go back to wootwoots link. There are links to examples using the Bosch relay and it will show which pins to use. You can get those relays just about anywhere (NAPA, PepBoys, ect) and they're cheap. The wire that goes across the relay contacts and then on to power the fans needs to be #12 sized wire. I would fuse it too (30amp). The wire from the fuel pump relay that controls your new relays can be something smaller since it probably takes less than an amp to operate.

[Ian]

sorry to be retarded, but where should i put this 30amp fuse?

should i get 4 and put them after each relay?

[Replicant_S14]

Originally Posted by mainevent212

where should i put this 30amp fuse?
should i get 4 and put them after each relay?

I put mine before.

...but, since you are using one signal (from the fuel pump relay) to fire all 4 relays at once, you could just put the pairs together and have one relay for each fan. Having 4 would make sense if you were going to contol them separately (or plan to later) but it sounds like you just want them both on high as long as the f pump is runnig.

[Ian]

yes sir that is correct, i bought 2 relays since that's all advance auto parts had at the time, and i was gonna pick up 2 more after their next truck comes (tomorrow afternoon) but i guess i'll just use the 2.


thanks

[SochBAT]

And that would also work?

[420sx]

yea. but i would use 2 fuses just for safety. the reason i wired it like this on mine is cuz i wanted to make sure the fans will be on if one of the fuses blow. so i just sautered an extra positive on the end and put it in another acc fuse. so total amp ideally for those fans should be more than 20.

[orion::S14]

Guys...I WOULD NOT wire these fans directly to the fusebox...use relays.

E-fans require too much amperage to route through tiny fuse box wiring. Do the same thing as the diagrams are saying, but use the wires coming form the fusebox to activate the relays, not power the fans.

- Brian

[axiomatik]

I completely agree with Orion. If I remember correctly, these fans draw something like 20-30 amps, which is way too much additional amperage to try to pull off the fuse box (or the accessory wiring). Use the Fuel Pump Relay to control two fan relays. Make sure the power for the fans is drawn directly from the battery through appropriately sized fuses and a relay that can be controlled by the Fuel Pump Relay. If you wire it like the schematic below, the fans will be powered from the battery, and will be turned on whenever the fuel pump is on. Wire the coils of the two new relays to the coil of the fuel pump relay. If wired like this, if one of your fuses blows, you will still have the other fan. Also, fuses are rated in Amps, not Watts like in some of the above drawings.

[MELLO*SOS]

nbrindley: Nice schematic. Are the fans 20-30a each or 20-30a total?

[Replicant_S14]

Originally Posted by mello88

nbrindley: Nice schematic.

Yeas it is! Thanks NB (...you CAD geek : ) )

Are the fans 20-30a each or 20-30a total? I was curious as to their amp draw...

Each. Just one of my alti fans blew a 20amp fuse. Use 30s.

Also, the thing about adding on to an existing fuse is: even if you swapped a 15A fuse with a 30A, you have to assume the wire feeding that fuse only has enough ampacity to carry the 15A it was originally intended for. For 15A you need #18 wire. If you put 30A over #18 it could potentially burn the wire itself before it blew the 30A fuse you stuck in there.

[MELLO*SOS]

Replicant: Thank you for the info. OT but do you have a link to a table that shows the safe max current rating vs wire gauge?

[Replicant_S14]

cut~n~paste pwnz

================================================== ======
| INSULATION TYPE: |
| RUW, T THW, THWN FEP, FEPB |
| TW RUH THHN, XHHW |
================================================== ======
Size Current Rating Current Rating Current Rating
AWG @ 60 degrees C @ 75 degrees C @ 90 degrees C
================================================== ======
20 -------- *9 ----------------------------- *12.5
18 -------- *13 ------------------------------ 18
16 -------- *18 ------------------------------ 24
14 --------- 25 ------------- 30 ------------- 35
12 --------- 30 ------------- 35 ------------- 40
10 --------- 40 ------------- 50 ------------- 55
8 ---------- 60 ------------- 70 ------------- 80
6 ---------- 80 ------------- 95 ------------ 105
4 --------- 105 ------------ 125 ------------ 140
2 --------- 140 ------------ 170 ------------ 190
1 --------- 165 ------------ 195 ------------ 220
1/0 ------- 195 ------------ 230 ------------ 260
2/0 ------- 225 ------------ 265 ------------ 300
3/0 ------- 260 ------------ 310 ------------ 350
4/0 ------- 300 ------------ 360 ------------ 405

* = estimated values; normally, wire gages this small are not manufactured with these insulation types.

BTW- I do industrial work and normally we oversize a little to allow for inrush or whatever. From what little bit of wiring I've done on the car, it seems like some of the factory wiring uses the max figure. I.E. the factory wiring for the fan looks like 12awg to me. If I were wiring a 30a motor circuit for a customer, I use 10awg cuz 12 seems a little too close. Maybe the fan doesn't quite draw 30 or they have different standards overseas *shrug* I really don't know. Just thought I'd mention it.

[Ian]

ok, i used your diagram actually, but my wiring for high power is like this:

Yellow and Black=Ground
Blue and Green=Power

Anyhow, I have one last question. Where do I get the Fuel Pump + signal from? I found the fuel pump fuse in the kick panel. That is the only labeled Fuel Pump anything i can find. I know this sounds stupid but it's the last thing i need to know. Everything else is ready to be wired up now.

[SochBAT]

Hot damn. I can't get my shit going. I tried wiring it up my way, and obviously it didn't work. When i tested them spliced the way i did, only 1 came on. Im still super confused about all that wiring and crap.

Times like these i wish i was a elec. nerd. how about some actual photo guys?

Since im reversing my AC fans, i should ground the positive, and route the negative to the battery. On that negative line, i should splice, connect to a relay, then a fuse, then to the FP?

[Ian]

so i tap into the power source at the 15A fuel pump fuse?

how do i tap into the positive feed at the fuse? i've seen little blade thingies that slip in there and i use a connector...but i donno where i can get one...assuming that this is the right thing i'm thinking of

[axiomatik]

You can tap into it that way, I'm sure some auto parts store has those blade-adapters you are talking about.