Electric Fan Wiring Advise

[Under Pressure]

I’m a good Plumber and a good mechanic but admit I am not real knowledgeable on automotive electrical.
Since I never use my GTX’s rear defogger I was thinking of disconnecting from this switch and hooking up my radiator fan to it, anyone know if the factory switch will handle the load from this fan?
Thank you in advance

 

[Nacho-RT74]

Why not run the fan with an automatic temp sensor?… then a switch to override it in emergency case.

 

[DGE330/NC]

get a temp switch . or just do it right and get a electric fan kit. it comes with the temp switch , and relay with a harness .

 

[Under Pressure]

This is why I came here for advice
Thanks guys!

 

[Canadian1968]

I run mine off a thermo switch (190 ON - 175 OFF) works perfect. Also wire power supply off the Alternator not the battery.

 

[pnora]

That switch alone will most likely fail. You need to use a relay with it. But as said buy a fan install kit with a thermostatic control and use that switch as a manual way of running the fans if needed. Cold Case makes a nice kit and Painless makes a basic kit.
Painless Wiring
Electric Fan Relay Wiring Kit Cold Case Radiators

 

[pnora]

I run mine off a thermo switch (190 ON - 175 OFF) works perfect. Also wire power supply off the Alternator not the battery.

I would never run off the alternator stud. I would run it off the battery. Alternator fails and all loads are now on that wire. Let the alternator do what it was intended to do.

 

[BeepBeepRR]

Feed a relay with 12 volts I usually just use ground as my fan switch. When the thermostat closes it grounds the relay and turns on the fan. Pretty simple wiring.

 

[Under Pressure]

After the advice and diagrams, this I can handle
Thanks again

 

[Canadian1968]

I would never run off the alternator stud. I would run it off the battery. Alternator fails and all loads are now on that wire. Let the alternator do what it was intended to do.

The alternator is ment to power all your accessories that exactly how the OEM system is wired .... If your alternator dies , it will draw power from the battery until that dies to.
The purpose of a battery is to provide that punch of power to to turn the starter and get the motor running. Once the engine is running the battery is just a stand by basically. Your alternator is instantly recharging the battery as soon as it starts. There are million threads about what side of charging system you want your load on . The Amp meter tells you all you need to know

Disconnect your battery and see how long the car keeps running. Then disconnect your alternator and see how long it keeps running ......

 

[pnora]

The alternator is ment to power all your accessories that exactly how the OEM system is wired .... If your alternator dies , it will draw power from the battery until that dies to.
The purpose of a battery is to provide that punch of power to to turn the starter and get the motor running. Once the engine is running the battery is just a stand by basically. Your alternator is instantly recharging the battery as soon as it starts. There are million threads about what side of charging system you want your load on . The Amp meter tells you all you need to know

Disconnect your battery and see how long the car keeps running. Then disconnect your alternator and see how long it keeps running ......

You need to go and look at how the cars are wired. Alternator is fused and goes into a buss system. All other loads are fused off the buss. The buss is direct off the battery. They do not feed directly off the alternator stud. You can do as you want but no one will see any of my cars hacked that way.

 

[BeepBeepRR]

My understanding is that alternators only charge at certain rpm ranges. I do not know if I believe they are charging right from the start. Have you ever sat and idled the car and the lights are dim? Then press down on the gas and watch them light up. I personally would not put that extra load on the alternator. I would run that off the stored power "Battery" that gets regenerated at higher RPMS. Throwing a 30 amp fan directly off the alternator would create a huge dimming effect since its a hell of a load on an alternator that is not spun up to actual charging rpm range. I would let the battery do its job and power the fans in my opinion. I'm not saying I'm right or wrong but it just makes sense that way.

 

[Nacho-RT74]

You need to go and look at how the cars are wired. Alternator is fused and goes into a buss system. All other loads are fused off the buss. The buss is direct off the battery. They do not feed directly off the alternator stud. You can do as you want but no one will see any of my cars hacked that way.

Alternator is not fused. Which is fused is the power coming from batt

 

[Nacho-RT74]

My understanding is that alternators only charge at certain rpm ranges. I do not know if I believe they are charging right from the start. Have you ever sat and idled the car and the lights are dim? Then press down on the gas and watch them light up. I personally would not put that extra load on the alternator. I would run that off the stored power "Battery" that gets regenerated at higher RPMS. Throwing a 30 amp fan directly off the alternator would create a huge dimming effect since its a hell of a load on an alternator that is not spun up to actual charging rpm range. I would let the battery do its job and power the fans in my opinion. I'm not saying I'm right or wrong but it just makes sense that way.

Hence why alternator is rated accordingly with equipment, while batt is just a reserve power storaging. The best is try to keep the batt as full as posible while the alt keeps feeding everything. Then alt upgrade is a must.

 

[Nacho-RT74]

I would never run off the alternator stud. I would run it off the battery. Alternator fails and all loads are now on that wire. Let the alternator do what it was intended to do.

With ammeter in line that is a mistake

 

[pnora]

Alternator is not fused. Which is fused is the power coming from batt

Bull crap. Look at all the cars and trucks the alternator is run through a HD fuse. Some over 150 amps. And if the alternator does not have a fuse it has a fuseable link.

 

[Canadian1968]

Bull crap. Look at all the cars and trucks the alternator is run through a HD fuse. Some over 150 amps. And if the alternator does not have a fuse it has a fuseable link.

So where is the fuse for OUR alternators/ electrical system ? The buss system or fuse box , protects each individual circuit in the system it's not limiting the alternator or battery for that matter.

A fuse is to protect the load that a circuit or accessory is trying to put on the system.

 

[BeepBeepRR]

Bull crap. Look at all the cars and trucks the alternator is run through a HD fuse. Some over 150 amps. And if the alternator does not have a fuse it has a fuseable link.

If you look at the diagrams for a 1969 Charger there is no HD fuse in the wiring. The only fused link is at the bulkhead connector which is on the starter relay circuit. I don't see any fused links shown in the schematics. However we all know there are at least 2 at the bulkhead connector. Also if you think about it. Why do ammeters cause fires if they are fused. Would it not pop the fuse before it burns down a dash? Oh wait there is no fuse in the charging system of a 69 charger.

 

[pnora]

So where is the fuse for OUR alternators/ electrical system ? The buss system or fuse box , protects each individual circuit in the system it's not limiting the alternator or battery for that matter.

A fuse is to protect the load that a circuit or accessory is trying to put on the system.

You have a fuse link. When you overload that the whole system is most likely dead. There are some variants depending on year. You take a older car and load off the alternator stud you are asking for problems. Worse when the alternator dies and all loads are on that old wiring. Failures will be in wires overheating, ammeter looking like a toaster element along with the bulkhead connections. If you have a bypass done and have a large 6 gauge wire or bigger to the alternator it will help. Just look at what has been done to cars for the last 25 plus years. They run a PDC with all loads including alternators of of fuses. Go out there and find cars, trucks, equipment that run off the alternator stud. Good luck with that search. If that was the way to do it the factories would have done it. Like I said no one will do a hack job like that on anything I own.

 

[Canadian1968]

My understanding is that alternators only charge at certain rpm ranges. I do not know if I believe they are charging right from the start. Have you ever sat and idled the car and the lights are dim? Then press down on the gas and watch them light up. I personally would not put that extra load on the alternator. I would run that off the stored power "Battery" that gets regenerated at higher RPMS. Throwing a 30 amp fan directly off the alternator would create a huge dimming effect since its a hell of a load on an alternator that is not spun up to actual charging rpm range. I would let the battery do its job and power the fans in my opinion. I'm not saying I'm right or wrong but it just makes sense that way.

If the motor is Turing the alternator is charging . If your over all system has to much load for the alternator itself then it starts to pull from the battery. The alternator should be able to handle all electrical load at idle if it can't your alternator isnt correctly rated for setup.

The system is based on push-pull situation . In a perfect world your alternator powers the vehicle and your Amp gauge sits in the center.