Here it is. Done and mostly polished. Please let me know if there's any errors I haven't noticed.
I'm going to add some more pictures and stuff before linking to it from my HowTo page so consider this a preview.
http://www.wildweasel.ca/j-body/HowTo/fanswitch.asp
And hey... if you use it... send me some money or something.
Any chance you can post an idoit version of your Diagram, for some of our none circuit literate people? I understand most of it, but im drawing a blank on some too.
Which parts are you drawing a blank on?
This is the feedback I need.
looks awesome man. great write up. did you put an LED in, and if so, where? or is it in the switch?
Desert Tuners
“When you come across a big kettle of crazy, it’s best not to stir it.”
There's an LED in my switch.
k. there's 3 "leads" on the switch, correct? how do you have those wired? I'm going to be doing this mod real soon.
Desert Tuners
“When you come across a big kettle of crazy, it’s best not to stir it.”
weasel, i can draw you an auto cad version of your drawing with some nice proper electrical symbols if you want it.. lemme know.
Injection is nice but id rather be BLOWN!
Z24 FReQ (Jarett) wrote:k. there's 3 "leads" on the switch, correct? how do you have those wired? I'm going to be doing this mod real soon.
It's in the instructions.
If there are three leads, the wire coming into the car from under the hood goes to +. The other two both go to ground, with the resistor in between the switch and the ground.
whitegoose wrote:weasel, i can draw you an auto cad version of your drawing with some nice proper electrical symbols if you want it.. lemme know.
That would be cool.
Post it up and I'll use it. Can you keep the same colour scheme?
I started by scanning the wiring diagram from my Haynes manual and then adding the red stuff.
Quote:
k. there's 3 "leads" on the switch, correct? how do you have those wired? I'm going to be doing this mod real soon.
Any switch with a light has three leads, power, ground and aux- the wire going to what your trying to switch on and off.
http://www.bcae1.com/switches.htm
^^^^^^^^^^^^^
THAT ONE IS THE SHIZZZZ
i wish i woulda had that years ago
Wild please read this before you make your instructions public, not insulting you or anything, but please read first, as your explanation of a diode is incorrect. any questions please let me know, ive done alot of this stuff before.
Click here
Its not how fast your car goes....its how much nerve the driver has to push it that fast.
use this link if you can't read the first one
Click here
Its not how fast your car goes....its how much nerve the driver has to push it that fast.
LittleBill wrote:Wild please read this before you make your instructions public, not insulting you or anything, but please read first, as your explanation of a diode is incorrect. any questions please let me know, ive done alot of this stuff before.
Click here
Thanks for the help man, but I'm really not sure what you're saying I've got wrong.
My explanation of a diode is correct, isn't it?
Quote:
Now is a good time to explain what a diode does and why we're putting one in this system. A diode acts as a one-way street for electric current. Power can flow one way through the diode but not the other way. By putting the diode between the new switch and the ECU, the ECU is still able to complete the circuit and turn on the fan but cannot detect that we've manually completed the circuit on our own. Without the diode, the ECU may be able to detect that the circuit has been completed and may throw a code indicating a failure of the cooling system.
Without the switch, there's a 12V source on the other side of the relay but the ECU is not completing the circuit. So the relay is not energized. When the ECU closes the circuit, the current flows from the 12V through the relay, energizing it, and then to the ECU. If we did nothing at all except add the diode in my diagram then it would do absolutely nothing. It would allow that current through as normal.
Now we go ahead and splice into the wire and make a ground. The relay works fine. From the 12V source, the power runs through the relay, energizing it, and then directly to ground. But what about the ECU? The ECU does not simply ground that wire. The ECU completes the circuit, supplying a ground. So when you supply a direct ground, you've shorted out the circuit that has the ECU in it and that's what throws codes. In order to keep the whole circuit complete, you need the resistor.
The ECU gets shorted exactly the same way that the diode in the switch gets shorted.
Putting in the resistor prevents this. You said the resistor does nothing.
Now we go back to the diode. At this point it's still doing nothing. But what would happen if, instead of the ECU providing a ground, it switch the wire to 12V. What if instead of switching between open and grounded, the ECU was switching between + and ground. When the ECU switches to +12V, no current should flow. If the ECU now detects a current, that means there's a ground elsewhere in the system. That would be a problem.
This is where the diode comes in. If the ECU switches to +12V, no current can run from it to the ground because the diode prevents it.
The diode might be unnecessary but it might not be. I'm leaving it in on the basis of it being a cheap addition and being better safe than sorry.
Incidentally, I'm not disputing you or arguing. If I've got it wrong I need to know so I don't go misinforming everyone.
I just don't understand what you're saying I've got wrong. Can you maybe do a diagram in Paint or something that explains the problem?
my diagram shows how it needs to be wired, click the link please, your comment about "power" when explaning diodes. you can't use the word power as the diode acts differently, depending on the polarity of the 12volt system, it works opposite depending on whether ground or positive is flowing through it
Its not how fast your car goes....its how much nerve the driver has to push it that fast.
looking at his drawing, and from what I gather from yours, you're not really saying anything different. if what your "I" means is the cathode side of the diode, then what you "drew" is identical to what he did.
if he were to reverse his diode in the circuit, and leave the switch open, there would be no current path for the coil in the relay through the ECU. for a diode to forward bias (to close the current path), the high side has to be on the anode, low on the cathode.
closing the switch would put a high on the anode, and if the ECU "wanted" the fan off, it will not send a ground to it's side of the diode (the cathode) and not see current flow.
if the switch is closed, putting a high on the anode, and the ECU wanted the fan on, sending a ground to the cathode, there would be current flow, and the ECU would still be okay.
Desert Tuners
“When you come across a big kettle of crazy, it’s best not to stir it.”
he wired it exactly like your link says, anode on + side and cathode on - side. his words were current can flow from anode to cathode, so put the cathode on the ecu side.
Z24 FReQ (Jarett) wrote:looking at his drawing, and from what I gather from yours, you're not really saying anything different. if what your "I" means is the cathode side of the diode, then what you "drew" is identical to what he did.
If I read his diagram correctly, the only difference between it and mine is that he doesn't have resistors.
That's what I had originally before realizing that I was shorting the circuit to the ECU that way.
That's how it was set up when it was throwing codes.
different schools of electronics learn different ways. my school learned negative to positive flow, some learn positive to negative. either way, his is still wired correctly.
Desert Tuners
“When you come across a big kettle of crazy, it’s best not to stir it.”
Wild Weasel wrote:Z24 FReQ (Jarett) wrote:looking at his drawing, and from what I gather from yours, you're not really saying anything different. if what your "I" means is the cathode side of the diode, then what you "drew" is identical to what he did.
If I read his diagram correctly, the only difference between it and mine is that he doesn't have resistors.
That's what I had originally before realizing that I was shorting the circuit to the ECU that way.
That's how it was set up when it was throwing codes.
right. I'm with you man. it looks good to me.
one way to test would be to close the switch, and turn your AC on. still shouldn't be a problem though. same ground going to the same 12 V.
Desert Tuners
“When you come across a big kettle of crazy, it’s best not to stir it.”
"But what about the ECU? The ECU does not simply ground that wire. The ECU completes the circuit, supplying a ground."
lol you just contradicted yourself completely, im just ribbing ya in fun, don't take it as a rip at all. all th ecu does IS ground the wire. your whole theory about the ecu sending positive is incorrect if you look at your schematic of how a relay works you would see that would do nothing then burn up the relay, it needs ground to close its connections.
the reason you see a code without a diode, is that the ecu can sense that the wire is grounded, even though the computer hasn't told the wire to ground itself. the diode is suppose to prevent the ecu from knowing there is ground.
"The ECU gets shorted exactly the same way that the diode in the switch gets shorted.
Putting in the resistor prevents this. You said the resistor does nothing."
diode don't short anything nor does the the ecu short, you complete connections, a SHORT is not what you want.
all a resistor does is change amperloads and voltage. period
your resistor does nothing
Its not how fast your car goes....its how much nerve the driver has to push it that fast.
which side is the stripe pointing in your diagram?
Its not how fast your car goes....its how much nerve the driver has to push it that fast.
LittleBill wrote:lol you just contradicted yourself completely, im just ribbing ya in fun, don't take it as a rip at all. all th ecu does IS ground the wire. your whole theory about the ecu sending positive is incorrect if you look at your schematic of how a relay works you would see that would do nothing then burn up the relay, it needs ground to close its connections.
you can put +12v on one side of that coil, +5v on the other side, and the relay would work. it doesn't have to be a ground. just needs current flow.
the resistor is there to put a high on the anode side of the diode in order to forward bias it, so the ECU can sense the current flow and not throw the code.
Desert Tuners
“When you come across a big kettle of crazy, it’s best not to stir it.”
ps, i've done this mod before, not trying to prove anything, resistors were not needed, the vehicle was a 2002 cav
Its not how fast your car goes....its how much nerve the driver has to push it that fast.
