I decided to take on my first wiring project ever yesterday and i ran into a problem that halted all of my progress. I bought a toggle switch and decided to make my electric fan operate off of that rather than the temp sensor. Once i figured out which wires did what, i realized that i have no idea how to get the toggle switch through the engine bay and on to my dash. Can anyone give me some info or tips on where to start looking; or if i will need to bring the wires through my dash or down by the pedals somehow?

 

Whatever you do, don't cut the red wire....or is that the blue wire?
Aren't there any stray, unused, or other holes in the firewall that you can share and pass the wire through? Also make sure the switch is rated to handle the amp draw of the fan or the switch will toast.
A relay setup is safer, but takes more wiring to hook up.

 

a relay set up? amp draw? SAFE? see you just spoke a different language. I tried looking for holes in firewall and i couldn't find any. Anyone know a good place to start looking?

 

The grommet for the tach wire, or you could get the drill out. A fused relay setup as 69 suggests would be better that running heavy gauge wire into the dash. What's wrong with the mechanical fan anyway?

 

Also make sure when you run the wire through the firewall,to put a grommet in the hole,so the metal doesn't wear through the wire and cause a short.As for amp draw,you need to find out the highest amps that your fan will pull,then get a switch rated above that amp rating.Example-if your fan pulls say 35 amps you would want a switch rated for like 40 amps,etc. these are not the real numbers,just trying to give you an idea of what you need to know.

 

Ohhhh ok. Well, right now what i have going on is an electric fan and it's supposed to be run off of a temp sensor. The way i had it set up was the temp sensor was zip tied to the upper left side(driver side) of the radiator against the hose that connects to the thermostat housing. I wasn't getting a very good connection between those 2 parts so my fan wasn't turning on...ever. So i figure it will be a lot easier to just flip a switch while city driving and then turn it off for highway.

So, basically I cut the 2 wires to the temp sensor and connected them to the 2 wires to the toggle switch. I did find that connected to the wire that hooks up to the positive battery terminal, there is an "in line" 25amp fuse. It actually blew when i accidentally touched the wire to some other metal on the car and the fan stopped working. I'm assuming that is just a safety feature. I'll go out tomorrow and follow the tach wire. I was thinking about running the wire under the fender where it bolts to the car, under the hood; and then through the door (right around the hinges) and then up through the dash or the center console.

As for the mechanical fan, if by that you mean the stock belt driven fan, i got rid of that a while ago to reduce drag on the motor. I also figured it would go nicely with the aluminum radiator back when i got that. Thanks for the tips and advice guys. As usual you have all be very helpful.

 

Running the wire up under the fender trough the door is the ugliest, laziest, most dangerous way to do it. I know thats how I did stereos when I was like 16. Then I would eventually were away the insulation on the wire and short out. Nothing like a smoldering dash to get your attention. It takes two minutes to find a hole. Five minutes to drill and gromit one. Be safe.

 

According to George Ohm, when working with DC circuits, as those in your car, this is all you need to know: I= E/R or I=P /E (lol)

I= Current in Amps (this is what burns you and your car)
E= Volts (Electromotive force, this is what shocks you and makes sparks)
P= Power in Watts
R= Resistance in Ohms

The fatter the conductor portion of the wire, the more current it can carry before melting or causing a fire.
The thicker the insulation, the more voltage the wire can withstand before arching and electrocuting you.

Wire current carrying capacity table:
Automotive Wiring

 

Well Pete, he (and everybody else) probably would have grasped the concept after your first sentence, but good thing you broke it down anyway. lmao!

 

Well alright then lol. When i get out of class i'll go into the garage and take a look at the fan output, what kind of wire i bought, and the toggle switch.

The one thing that is kind of confusing me about drilling a hole is the size. I mean, how small do they make grommets? also, if there is any room around the wire, won't the smell and sound of the motor be much more noticeable while driving?

And Pete, thanks for the wiring lesson. 69 is right, well kind of, I STILL don't know when i'll use it but im sure i'll know when the moment happens. It will be my first under the hood epiphany.