dude you can buy all this outstanding hardware haha at radio shack...a potentiometer is like a volume dial...only controls how much output either volts or amps that comes out of it by twisting it.

 

ok, but how does the potentiometer get connected in line with the fan speed wires? would you tap into the wire?

 

From the potentiometer the line would go through the dash (where the rest of the wires go through the firewall i.e. guage cluster and AC and stuff like that) and then you can just zip tie that wire to the same group until you have to branch off and go to the fan....you'd tap into it(anything but the white wire), called splicing - leaving the original wire there but giving this new wire access to it kind of like a T-connection for the electricity flow so to speak.

 

Why in the world is this so hard?????

Potentiometers? Cutting into PCM wires? You should stick to computer engineering Avenger, youre automotive schematic reading isnt up to par today.......


1)Look at your fan......pick which ever wire is the "hot" wire for whichever speed you wanna control (Light Blue for low, Grey for high) Now cut that wire so there is several inches between your cut and the fan.

Get your relay. You want a 4 pin(single pole single throw) relay capable of handling 30 amps.
Get some wire, you need SXL or TXL wire. It has a crosslinked polyethylene insulation, is rated to 257degF, and is what your car already has in it. Youll need 4-5ft of 12ga. and about 6ft of 18ga wire.

Get some fuse holders, youll need two. Get weather sealed ones that use the same ATM mini blade style fuses as the car, youll want one with 12gauge leads rated to at least 30amps for the fan, and one with 18 or 16ga leads for the relay control, youll also need a (brown)30amp ATM fuse and a (purple) 3amp ATM fuse.

Get a switch, all you need is a plain old SPST switch rated for 5amps, get whatever you think looks pretty.

Youll also need some crimp/sealable terminals to attach wires to the switch and to the relay, youll also need some crimp and seal style butt connectors.

Take your 30amp holder, and attach one end of it to pin #30 on the relay, the other end will go to a battery voltage lug in your fuse block.

Take your 3amp holder and attach one end of it to pin #85 on the relay, the other end will go to a battery positive voltage lug in your fuse block.

Take your 18ga wire and cut off about 2ft, attach this to one side of your switch and then to a good ground inside the car. Attach the remaining 18 ga wire to to other pin of the switch and run it out to the fuse block are where youre going to locate the relay. This end of the 18ga wire attaches to pin #86 on the relay. You just completed the relay control circuit.

Now take your 12ga wire and go down to the already cut fan feed wire. You need to crimp a butt connector onto just the fan wire coming from the fan, the you take your 12ga wire AND the other side of the cut fan wire and stick BOTH of them into the other side of the butt connector, crimp them in place then heat it up and seal it.

Now take the other end of your 12ga wire and attach it to the last open pin on the relay(#87)

TAADAAAH......youre done. You now have a properly protected, relay controlled manual fan switch. Go out and impress your friends.


If you dont understand anything Ive said here,lack the proper tools, skills or training or you dont have access to any of items I list, DO NOT even attempt this. Using wire, relay, switch, fuses or connectors with specs different than what I have detailed may cause personal injury or death, property damage, conflagration or general LAWLing at your inability to create a simple circuit. Even if you do do it right you do so at your own risk, your car isnt meant to operate in this fashion

 

This is a good pic of how a relay with a switch



I like this better than schematics, I hate schematics. Tanks schematics suck.

 

I dont like setting up relays that way if possible, thats got a high side switch, I always use a low side switch if possible, makes the switch last longer, and almost zero chance of a short in the wiring you do inside the car burning your interior up. That is also a lighted switch.

 

What's the difference between a low and a high side switch?
Thanks, Maven

ps. I know its lighted, its just an example of what i thought you were talking about minus the lights

 

high side/low side is in reference to how the circuit is controlled.

A high side uses the switch to supply power to the relay, this means youve got full power going through switch and your firewall.

A low side uses the switch to supply ground to the relay, so youve just got ground(and therefore very little potential energy) going through switch and your firewall.


If a high side circuit grounds out it sparks, creates heat, burns things, blows fuses.

If a low side circuit grounds out it turns on relay.

 

thanks for this info.

So like this

 

yup except are fan is the load and it has its on ground, you need to put power into the relay.

 

Egh I swear people don't read things, they just skim over and automatically assume someone sucks at whatever they're talking about -
look at the original drawing on the page, my schematic reading is fine - the only thing that keeps the relay powered off is a ground controlled by the PCM once the pcm supplies the ground to the relay it then turns on and allows current to flow DIRECTLY from the battery+, through a fuse and the relay and then out to the fan(like I said its fine)...and I said in my last post "if you cut into your pcm wire then your a braver man than I." (to control the relay ground as well as letting the PCM control it) If your going to paraphrase and give advice, please at least repeat what was written, as that was only one way of doing it. ...your starting to sound oddly like Fox News....

and as for not approving my way of doing things, we all have our own way for sure, and its no big thing if you think mine sucks. i did like your fuse connected right after the battery+ point....thats a good idea, but the big thing for me is yours has you working directly with/under the fuse block, and after just going outside, my LS only has 1 open relay point which would handle that relay(maybe not all cobalts have this point open though?), but most people don't want to start messing with that kind of stuff, my way was just simpler thats all, not to mention you don't have to worry about getting any homemade connections wet except for the one on the fan wire(as all but that one are inside the car)...

but dude your way is rockin and i'm glad you showed us a proper way of doing it i just favor the easy-in/easy-out way in case I ever decide to sell the car somewhere down the line - not to mention i'd enjoy being able to control how fast(i.e. LOUD) my fan is based on the conditions...thats just me though (and whats with the disclaimer at the bottom? I swear you'd think that stuff would be obvious)

not to steal the thread by the way - but does anyone know why they won't put new tires on teh front unless you buy 4 of them?

 

I did read what you said, and I saw that you know the PCM is controlling the fan. But you were acting like you were splicing right into the PCM and it was some big deal....ie: it requires significant bravery to do so.....The fan realy contro wire actually doesnt go directly into the PCM, it is a 2 piece circuit, you would splice into it in the second section, this would be a very simple low control circuit you needed to make but as you pointed out its hard to access these wires, thats the only reason I dont recommend doing that way.

You dont need a spare location for the relay, you arent installing it into the fuse block or even doing anything more intensive than taking the lid off the fuse block. You would simply be attaching the fuse lead to an open hot terminal in the fuse block.

See the open silver tabs on the end of the fuse block with the DRL fuse? you would just plug right into one of those, or place a terminal under the big positive lug on the lower left.

Thanks, youre way is definitely easy but I just dont think installing a potentiometer in the dash with a a hot 30amp load connected directly to it is really that safe. Especially since your second way doesnt have any circuit protection. There is a reason that you wont find high amperage circuits with high side switching in the cabin of the car....****, the ignition switches in our cars are wired win with 22ga and dont ever see more than 2amps.

Youd think it would be, buts its obviously not. Some people lack even very basic understanding of electrical systems and circuits, and any custom fabbed circuit is a quick way to torch your car if done wrong.

 

ok I have a question...follow my description, start at the battery+ rod, go to the closest relay, go to the next one directly to the right, and then go to the right and down and that third relay, I don't have a relay there???

 

I'm working on this. I'm running a switch that just grounds out the relay(cooling fan 1) to turn the fan on.
I've already found out this does work.
Question: Do I need a fuse in between the ground from the relay to the switch?

 

No. it doesnt need to be fused if youre just supplying the relay a ground.


Avenger, whats your question?

 

Just hooking up a ground to a switch and then ground out the relay is the best way. This is how I have my low fan hooked up. Question is if I want to make a two switches, one for low and one for high fan, when high fan relay is running is low fan relay running too?

Any clues guys? Wether the high speed fan relay runs with the low speed fan relay or by itself?