Cheap Fan Controller To Relay...

If you don't have a high current alternator, you can forget about using an electric fan. The stock 65 amp alternator on 86-93 Mustangs isn't big enough to run the fan and the rest of the car. If you have a 94 or later Mustang, the stock 3g alternator should be fine if it is working correctly.

Using the controller as a pilot controller to turn on a lager relay should work OK. Just be mindful to use the proper size wire and fuse it accordingly.

Wire size current table:


Solder any splices in the wire and cover the solder joint with heat shrink tubing.
Heat shrink tubing is available at Radio Shack or other electronics supply stores.

See the video below for help on soldering and heat shrinking wiring. There is a lot of useful help and hints if you don’t do automotive electrical work all the time.

View: http://youtu.be/uaYdCRjDr4A

volvo or BMW fan relays.. Do a google search for them

75a bosch or tyco relay and a $4 switch works fine. The $4 switch turns the relay on, relay turns fan on. No need for a cheap controller to turn a relay on, waste of money.

Ebay. tyco or bosch 75a relay. No need for controller.

Yes. The switch will turn the relay on which in turn, turns the fan on. You will want to do a 130a alternator conversion as well.

Grn92LX said:

Ebay. tyco or bosch 75a relay. No need for controller.

Click to expand...

Bad, bad advice...

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.

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 or more amps and you need to use #10 or #8 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 temp sensor in the diagram needs to match the thermostat in your engine. The preferred arrangement is to have it open about 5 degrees above the thermostat.

Alternate placement for a temp gauge sender:

Revised 24 July 2011 to add better temp sender location description and the necessity to loop the fluid flow through the heater circuit.

How it works:
If you want any kind of operation similar to stock, the ECT/heater feed line is the best place for a temp sender or fan thermo sensor. After all, the computer uses the ECT to pick up data on how warm the engine is. Putting the temp sender in the same line as the ECT is a simple way to get the best possible accuracy at minimum cost and complication.

Some things to keep in mind:
Just be sure that you haven’t blocked the coolant return because of a leaky heater core. For this to work correctly, the coolant needs to flow from the ECT sensor tubing back to the water pump. That means a leaky heater circuit gets looped rather than just plugged up. Join the rubber hoses together with a hose splice from Home Depot rather than plug them up.

Where to put it:
Use the heater feed that comes off the intake manifold that has the ECT sensor in it. Cut the rubber hose that connects the manifold water feed to the heater and splice in a tee adapter for the temp gauge sender. That way you will get the most accurate temp readings since the coolant is always flowing through the heater circuit in a stock car. Remember to include a ground wire if you use an electrical sender.

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.

15 years no issues with my bosch 75a relay and $4 switch. Never said use a switch w/o a relay, that would be bad advice.

Bilison, you do not need a controller with the 75a relay.

Grn92LX said:

15 years no issues with my bosch 75a relay and $4 switch. Never said use a switch w/o a relay, that would be bad advice.

Bilison, you do not need a controller with the 75a relay.

Click to expand...

When you say switch, are you referring to a toggle switch that you manually flip on and off? I think for a driver, sometype of automated control is needed, which is what jrichker is pointing out.

Joe

Yes that was what I was referring to. I never minded having to turn a switch on, it's located right next to the temp gauge anyway. I'm always looking at my gauges.