Electric Fan wiring question

What controller are you using?

If it has a relay and temp sensing mechanism, you can use VPWR or the low coolant light to power the coil on a relay.

I tapped off my ignition wire behind the ignition switch and ran the wire through the rubber boot on the firewall.

ya what i did too, the fan was going off when the car was off. The sensor was tooo sensitive. So its always on when cars on and off when off. Im sure hook up through ignition.

If that controller doesn't use a relay, be sure you're not powering the fan with your ignition.

If you don't have a high current alternator, you can forget about using the fan. The stock 65 amp alternator isn't big enough to run the fan and the rest of the car.

Switching a fan on and off manually is a bad idea. Too many guys have been distracted (hot girl kissing on their neck, too much to drink, dog tired and not thinking clearly) and cooked things because they forgot to flip the switch. An equal number have forgotten to turn the switch off for the same reasons and run down their battery.

The best fan controller available today is a DC Control unit. www.dccontrol.com. Cost is about $110. Be prepared to wait 4 weeks or more to receive your controller once you have sent in your payment. The controllers are custom made in small lots and lead times can stretch out.

Next best is a SPAL controller - $70-$190 See http://www.spalusa.com/fans/automated/accessories/fanpwm.html. Ebay will have the controllers for the $70: do a google search and see what you find.

At the bottom are the Hayden or Imperial controllers available through Advance Discount Auto Parts and AutoZone. The non adjustable one is about $30 ( Hayden 226206) and the adjustable one is about $60 (Hayden 226204). I recommend you do a Google search on Hayden and the part number for more info.

Do not use a simple on/off switch without using a relay. The current load can burn up the typical cheap automotive switch very quickly. The fan draws 30+amps and you need to use #10 wire on the fan power and ground wiring.

If you are good with electrical stuff (90% of the people here aren't), build your own controller. The numbers on the diagram (#86, #87, etc) refer to the numbers on the bottom of a typical automotive relay.



Note that the thermostat switch in the diagram isn’t really suited for the job. You’ll have to do a Google search and find your own.

This version of the fan controller will continue to run the fan after the ignition switch is turned off, just like most new cars.
To allow the ignition switch to control the fan so that it does not run when the ignition is off, connect the relay contact #86 to the red/green wire on the ignition coil or to the red/yellow wire on the coolant level sensor.

If you are an experienced electronics tech or electrical engineer, email me and I will send you the prototype drawings of a fan controller that is probably as good as the DC Control unit. It is a build it, troubleshoot it yourself item. I will not build or troubleshoot units, so it is not suitable for anyone who isn't really good with electronics.


Alternate placement for a temp gauge sender or temp switch/temp sensor for an electric fan. Use the heater feed that comes off the intake manifold. Cut the rubber hose that connects the manifold water feed to the heater and splice in a tee adapter for the temp gauge sender. Be sure to use the same water feed line as the ECT sensor. That way you will get the most accurate temp readings.

Tee adapter info:
Make a pilgrimage to your local hardware or home supply center and get some copper pipe and a tee that fits the temp gauge sender. Solder two pieces of copper pipe onto a copper pipe tee with threads in the tee part. Find the correct brass fitting to match the temp sender threads to the tee fitting.

another awesome post as usual jrichker. This is why I love this site!

So i run #86 to the ignition coil. lol i know thats exactly what jricker said above.. But it says to run it to ground. But i assume the coil is grounded obivously. I want it to shut off when ignition is off.

Also, so i hook up each power wire off each fan to a 40a relay, which terminal? Then hook up the power fan wire coming out of the controller relay to that 1st relay, but which terminal?

I know im stupid. Id rather look stupid then burn the car down. So let me add, the power wires coming out of the 40a relay for both fans is not 10 guage, its 14awg. Not cool or what? Each power wire is on a 25a fuse, which i read blew up, so put 40a fuses and it worked fine. with this controller, hayden 3652.

Also, just run the negative fan wires straight to grounds, or to the relays, then ground the relays?

Negatives on the fan motors go straight to ground. What fans are you planning on using? Depending on what fans you may need a bigger relay.

Terminals 85 and 86 can be power or ground each. Basically power one side, ground the other. jricker is calling for 86 to be power, your instructions above call for 85 to be power. The two options to get power that jricker is referencing would be the ignition switch in your diagram.

Right. Contiur fans. It technically does need a bigger relay. I got a 40a and a 70a. But should still turn on if wired right.

My power wire for the relay is coming off the starter solenoid where my positive cable terminates at. Ima run it to battery direct for a test, i just noticed it said that. Maybe that gives me power. Lol.

Foxslider said:

Right. Contiur fans. It technically does need a bigger relay. I got a 40a and a 70a. But should still turn on if wired right.

My power wire for the relay is coming off the starter solenoid where my positive cable terminates at. Ima run it to battery direct for a test, i just noticed it said that. Maybe that gives me power. Lol.

Click to expand...

See my post in this note, I updated the links and have diagrams that will provide you with the information that you need,

Thanks.
Do you know if wiring the relay input power to the starter solenoid (battery cable side) would be the problem?

It has power when i check it with test light.

Starter solenoid or battery positive post, same thing.