Radiator fans not running.

Well yes and no.
Yes you can install a switch, but you need to run the fan from a relay instead of thru the switch. Most switches aren't tough enough to handle the load.
It would be just as easy to run the fan from a relay and connect it to something that is hot when the key is on. Or hook the fan relay you have now to something hot with the key on.

Could have air pockets in the cooling system.
Will the radiator fan come on when you turn on the a/c ?

It may already have a blown head gasket. The max pressure on the cooling system in normal conditions is 18psi.
How do you know the fan or fans are ok ? The computer signals the relay to turn the fans on if the engine temp reaches 220 degrees or you turn on the a/c. If the temp sensor does not have coolant to tell it the engine temp, the fans won't come on.
As for a toggle switch, you would need a relay mounted close to the fans because they will pull too much current thru only a switch.

-Why you want to hook up a switch to the fan...? You want to turn it on when you want?
-No Problem. Here some basic installation.
-Connect the hot wire to the positive (+) battery terminal.
-Connect both left over wire to the switch. Then connect 1 wire from the other side of the switch to ground. you should be good to cool down.

Good lucj

Mai

i dont know what you mean, if you are tying to put a toggle switch in then run one wire from the fan to a ground on the truck and a wire from the toggle to the fan you will also need a hot wire from the battery to the toggle with a fuse inbetween, but the first thing you want to check is make sure the fuses and the relay are good and you have no broken wires if they are good then hook up a neg- and a pos+ wire to the fan if it comes on the change the temp sensor and the fan should work on its own when the truck gets hot

My friend had a geo metro and his radiator fan stopped working due to a wiring problem and he had to run a toggle switch to it and then it worked fine. Try hooking a live wire to the battery to the fan and see if it comes on and if it does just hook it up with a toggle switch.

use a straight wire and run it in the car hooked to a high amperage toggle switch. works when these things go whacked out.

well you see the relay is built to switch a higher current circuit using a smaller current. it is a safety hazard as using just a toggle switch will allow too much current to flow thru the circuit. you should replace the relay. now if after you replace the relay the fans dont work but the fans are good(ran power wire directly to fan for testing purposes) then as a temporary measure you wire a switch to Control thr relay(relay actually handles the fan current). find the fan relay. it should have 5 pins. on the case of the relay there should be a diagram.


the numbering should be the same.

using an ohm meter checkthe relay socket pin86 with red lead, black lead connected to ground. if zero ohms, then that is ground and pin85 of relay socket is +. pin30 should read 12 volts with meter, run wire from here to one side of a toggle switch located near steering wheel so you can access it when you start car. other side of toggle switch runs to pin85.with the small wires into the relay socket still in place, plug in relay. throw toggle switch to on and if everythings connected, fans should come on.

You can check if the fans are working by turning on you Air conditioning. They should run constantly with the A/C on.
Also bear in mind that the fans do not normally come on until the coolant temperature hits around 225-228 degrees.

it's controled by a fan switch, when it get to a certain temperature the switch closed and power the relay which makes contact to feed power to the fan.
you can do a toggle switch like that, make sure you have right size of wires and the switch can handle the load, and the fuse is the right amp.
the possible damage is that if you ever forget to turn off it will drain your battery and make the fan motor go bad quicker.