Black R

Long story short:

I have a 2jzgte in my 240sx.
I'm using dual fal puller fans on a manual switch.

I keep melting the switches!

Ive used 30amp and now 50amp is the last one that melted!

Should I use a thicker gauge of wire to and from the switch?
Will that have an effect on how much heat is generated and transferred / conducted to or through the switch?

*I have a 30 amp fuse inline with the switch also.

Cobb2819

a toyota motor in a nissan?? that's why you're melting switches. just kidding. you might want to use a relay instead of running the current through the switch. if i remember those fans should have a relay on each one. what is the fan motors current rating??

joeymc13

Yeah, what Cobb said...

I would def run a cpl relays, and just send ground to the coils of the relays from the swithces...

angel_i

Use thick wire and relays. What gauge are you using?

Black R

i didn't think of using relays.

what size / spec relays should I use?

EmminoDaGreat

you gotta use relays when doing the fans on those swaps...

2point2

Why?

Because of inrush current.

Whenever you size a fuse, switch, relay, etc you have to keep in mind that, in this particular case - an electric motor, will suck a lot of juice as it ramps up to speed. A basic VOM will only show the continuous current. Every time you turn on the switch you're drawing well over 50amps for tiny amount (spike) of time. You're slowly burning out the switch over time.

Here's a like you might appreciate: http://www.fordmuscle.com/archives/2...cfan/index.php

Please don't 'use relays'. Get a proper relay for the application.

joeymc13

There are so many types of relays... You need to find some that can handle the current draw of the fan motors. They should have atleast 4 pins, they will all be labeled differently. Every relay will have a coil. What do you want to use to trigger the fans to turn on? If just toggle switches still, just have the switch send either 12v or ground to one side of the coil, (I would have it send ground), then have the other side of the coil be the opposite polarity of what ure triggering the relay, (in my case, since I would be using ground as the trigger, I would have 12v on the other side of the coil. Every relay would have a common contact, in this case, you want that termnal to go to the fan, and the last terminal will be your normally open contact, in this case, you want this pin to have 12v. If your relay has a normally closed contact, just leave it empty. Wire size is important, but I can't answer for sure without knowing the current draw on your fans. my guess is that you will b fine with 16awg wire, as long as your relays are installed close to the battery and fans. Fuse all 12v wires as close to the power source as possible!

joeymc13

Coil pins- 1 should be your trigger, the other pin should be opposite polarity of the trigger.

Common- 12v output to fan
normally open- 12v
normally closed- empty

I don't see these fans drawing more than 25 amps of current, so a standard Bosch style auto relay should work fine, here is how I would wire it...

85 (coil)- ground from toggle switch
86 (coil)- 12v fused
30 (common)- 12v to fan
87 (normally opened)- 12v fused
87a (normally closed)- empty

Black R

Thanks Joey!

I see you're in Atlanta too; I'll buy ya a beer anytime.

I'm trying to find an equivalent relay at napa now...

Black R

Ok, so the guys at the local napa are nice but can only look up stuff by replacent part # or year/make/model. :/

And at $18 for a relay, it could be some costly trial and error.

I remembered that I have a known good relay in my console, will it work?



Maybe someone can decipher it for me?

Bob_760

It's hard to see what 3-4 is. 1-2 is your coil, 6-7 is normally open and it looks like 3-4 is normally closed. Test it for continuity with a volt meter 6-7 should have no continuity and 3-4 should have continuity. I don't know how much you know about relays so I'll explain everything. To ensure you have everything correct check for continuity on 3-4 and 6-7, then supply 1-2 with 12v and ground (dosen't matter which is which) then re-check 3-4 and 6-7 they should change. If you want to try this relay post your results from this test and I can advise further, from the looks of it...

1 (coil)- ground from toggle switch
2 (coil)- 12v fused
6(common)- 12v to fan
7 (normally opened)- 12v fused

Either way I doubt that relay can handle the current, what size fans are they? Do you know the model number? Some FAL fans draw 20a each and even more on startup so I personally would use at least dual 30a relays. You can use joeymc13's "diagram" just use two relays. It would look like...


85 (coil)- ground from toggle switch 1
86 (coil)- 12v fused 1
30 (common)- 12v to fan 1
87 (normally opened)- 12v fused 1
87a (normally closed)- empty

85 (coil)- ground from toggle switch 1
86 (coil)- 12v fused 2
30 (common)- 12v to fan 2
87 (normally opened)- 12v fused 2
87a (normally closed)- empty

As for napa not being able to look it up this isn't a "part" per se. It should be on the shelf somewhere. (Electical aisle with wire/fuses etc?)

joeymc13

Yeah, i definitely meant for you to use two relays. i made some phone calls for you, advanced auto carries them for $7.49 each, and bestbuy carries them for $9.99 each. You can still use one toggle switch for your trigger, but definitely use two relays! When you ask for the relay, just tell them you are looking for standard universal automotive relays. They will usually have 5 pins, but like I said, just don't use the normally closed contact.

Black R

Thanks so much guys. I'm a real nub to relays.

I mean, I can solder pretty decently and splice and things like that, but I've never really had any dealings with relays.

I did some research today, and it looks like the relay above is single pole double throw.

I'll go check advanced auto right now!!!

Unfortunately I don't know what fal fans they are - but I know they pull a LOT of current. I can't find any markings or anything on them, but they are the shrouded dual fans - so I was thinking at least 30amp or maybe 50amp in case of spiking?

Now that I'm digging around in the wiring of the car, I noticed some other **** that kinda scares me - the way the wiring was done for the ecu and just other general previous owner hackjob stupidity. I'll post another thread about that later... :/

joeymc13

It's all good, we all had to learn abt relays at some point, we weren't born with it, lol! Most of the universal 5 pin Bosch style relays are rated to handle up to 40 amps of current each. They are also usually spdt relays (single pole, double throw). I wouldn't think that u would need much more current handling than this, based on the fact that most of the stock alternators in our smaller Asian cars are usually rated around 70-90 amps output. If we are toasting 80 amps worth of relays, I would just have to say, wow.... Anyway, I hope this info gets u good to go, and I hope u weren't playin when it comes to the beer comment u made, bc I can't turn down beer... Mmmmmm.... Beer....

Black R

No joke on the beer offer!

I'm at advance auto right now and they only have one 4pin 30amp 12v relay!

Driving to the next one now!



It's got pins for 85, 86, 87, and 30. $7.79ea

joeymc13

That relay would be fine as long as your fans aren't pulling more than 30 amps of current, but since we don't know how much current your fans draw, then yeah, on to the next one! A 4 pin relay is fine, the 5th pin on a spdt relay isn't going to be used anyway...

joeymc13

The more I think abt it, u said you had a 30amp fuse in line with your toggle, and u weren't popping that fuse, right? You were just melting the switches, right? More than 30 amps wouldve popped that fuse, so, if u can't find a 40 amp relay, scoop those up from advanced, I would have to think they would be okay, considering u never blew that 30amp fuse from your previous setup...

Black R

Ok found another brand at the other advance auto, 40amp for $4.19 ea!

I bought 2 more just in case!

Black R

Oh and I got some 14 gauge wire now too!

I'm not taking any chances!

joeymc13

That will work, sounds like ure good to go! Best of luck!

Black R

Woot!

Done!

It looks like the existing wires were 18ga...

I still need to clean it up a bit, but it works good now!

And the switch doesn't get hot at all anymore.

Joey and Bob, I definitely owe you guys a round!

joeymc13

Don't think I forgot about the round of beers you promisied, LOL! What city are you in, Im gonna have to meet up with you! I hope everything is working okay for you! I'll meet you soon!