ok i know that you have to use a DPDT switch to tap into the relay on the upper left hand corner of the engine bay.

anyways, what kinds of DPDT switches do yall use for this..............one thats only got 2 positions??? or one that has a center, up, and down????

and also if its only a two position how does it work??

is it that when its in the "low" switch position that the computer just tells the fans to come on whenever, but when you switch it to the "high" position they come on all the time...............OR

is it that way with the Center, up, down, switch??????.......................i am just wondering whether or not i am going to have to turn the fans on all the time or what is going on.


If i knew how the wiring schematic sorked then i could do this, but unfortunately i dont......................

is there a way that i can set it to where the fans come on by themselves, but that i can control them if i want too or is it that when wiring this switch i will ALWAYS have to control them manually?????


I know there were a lot of questions, but if you all wouldnt mind giving yalls help that would be great.



Thanks guys, Scott






AND........................on second thought....................DO YOU HAVE to use a DPDT switch????.............(if you need a center, up, down switch then i know you do).........but if you dont then why cant you use a SPDT switch

i mean DPDT switchs are mainly used to switch polarity and if all you need is just two prongs for 2 wires (thus 2 power ends) then why cant you just splice the wires together and put them on the 1 prong end of a SPDT switch then just branch from there.



IF ANYONE HAS DONE THIS THEMSELF OR HAS KNOWLEDGE ON THIS SUBJECT PLEASE PM ME BECAUSE THERE ARE A FEW MORE QUESTIONS THAT I HAVE!!!!!


THANKS GUYS,


Scott

 

personally i didn't want to go thru the headache of trying to wire up a switch myself so i just got one from thunderracing. it was like 70 bux. but it was a plug and play setup. no wire chopping or anything.

1. use a 3 position swtich. center = off, up = hi, down = low.
2. http://shbox.com/1/fan_sw_diagram2.jpg go here. it is a diagram that shows you how to wire it up.
3. the only way you can make the fans come on by themselves is to have the computer programmed. which if you decide to do that...i suggest Ion at madz28.com. he does great work.
4. you could use a SPDT switch, but then you would have to decide what speed you want your fans to run at when you switch it on. or you could just have the fans run all the time, just switch between hi and low. I would suggest DPDT switch so that you can turn them off to prevent premature failure of your fans from overwork.
5. DPDT is Double Pole Double Throw switch. that equals 3 positions. on/up, off/center, on/down.
6. SPDT is Single pole Double throw. 2 positions. on/up,on/low or on/up, off/down.

Hope this helps.

 

Most all DPDT switches I have seen have an off position. I mean, why have a switch if you cannot turn it off?

With the fan switch off, the fans operate normally as controlled by the computer.

When you flip the switch to low-the fans come on low.
When you flip the switch to high-they come on high. It's that simple.

If you want to be able to control low and high speed separately, you must use a DPDT switch. Polarity is not the issue, here, when using the DPDT switch.

 

I got a switch for HBH racing. I had to work with him for a couple weeks because I needed a custom switch. Great customer service and it only cost me like 35 bucks for the switch. I did need to splice a few wires but it was very easy and if you were to build a switch yourself then you would have to splice those same wires anyways.

 

thats what i was wondering if they were going to do or not.......your diagram looked kind of weird to me...............maybe it was because i was misunderstanding it. I dont know

yeah i knew polarity wasnt the issue, but i was trying to understand how it worked.............the diagram you have. what are all the wires????

sorry for my incompetance, but there were no labels for the wires. are they any grounds or are the left black wires just power and the top and bottom (blue and green) wires go to the computer wire???

Thanks SHOEBOX

Scott

 

i just looked at your diagram again i understand the part about the wires tapping into the blue and green fan wires.......(sorry my brain wasnt working the first time i looked at it i guess..............................SO all i need to know is....are the black wires (going to the positive posts on the switch) 12 volt power wires??????


if so why are one of the ground posts connected by a power wire and why does one post not have a connection to it??????

or are just the red wires going to the LEDS 12 volt wires.............if only the red ones are power wires then how can the fans cut on without power from the switch.

I know the answer to all the question are simple im sure (but for some reason i cant understand this one)


Thanks

Scott

 

There is no voltage of any kind switched by the switch-only ground (safest way to do it).

The black wires are the ground sides to the optional LEDs. The only 12v needed (the red wires) is to light the LEDs .

The green and blue wires you tap into are wires from the PCM to the fan relays (not to the fans, themselves). The PCM sends a ground to the relays to operate them (you want your manual fan switch to do the same thing).

You can look at the fan control schematic. It will tell you how the normal circuits actually work. It might confuse you more, though.

 

Thanks, i understand now.......................i was just having a dumb moment i guess. i understand how it works, After looking at that site i understand now. I guess i didnt know what the wires were tapping into (the pcm), but now that i understand how that works i know why the switch has to be wired up that way.

Thanks man, Scott

(oh and about those 2-way dpdt switches.........i found a lot at radioshack, and the only 3-way dpdt switches i found were ricer style, but maybe i can get one and use a dremel to customize it.)



another question real quick would you mind shoebox???

i have a MSD RPM acitivated window switch for my nitrous kit........well it has a white wire thats suppose to be tapped into the the TACH. Where is the wire that im suppose to be tapping into???? is it the white one on the same relay as the fan wires or is there another one i should tap into???

Thanks man, i appreciate all your help.......

Scott

 

The white wire on the coil should work for that.

 

ok, thanks for all your help man.......i really appreciate it

Scott