Electric fan and thermostat setup help please

No information about what kind of fan controller you have.
No info about your car's model year, EFI or carb, no mods listed. Makes it hard to troubleshoot when we don't know what you have.

Therefore, no clue as to which wiring diagram you need. The wiring changed several times between 79 & 95.

Since my cyrstal ball is in the shop getting re-polished I cant help you...

That's why it is a good idea to use the sig under the user control panel (User CP) option. It allows you to post your car year & mods, which help greatly when troubleshooting things. No, it is not there for us to snoop and see any "Secrets" you have hidden away under the hood. Be a good stangnetter and update you sig for future reference & don't keep us guessing.

The thermostat rating (180, 195*, etc) would have been real helpful. Also note if it's a balanced or non-balanced stat.
And tell us about the fan. Sounds like you might have an Intrepid fan. Depending upon the generation, you wire it up differently to run low vs high speed.

We're still hurting for info. Without knowing if the t-stat is balanced, I'd set the controller to start running at 197* and go off at 190* (as a starting point).

Some Chrylser fans will have both power wires powered to achieve high speed and some fans will overload the motor if you power both low and high at the same time. Without more info on the fan or controller, it's hard to help.

The power for the fan needs to come from the battery side of rhe starter solenoid. The fans pull 30 amps or more and that is too much current to take from any of the wiring in the engine compartment.
A part number or description (mak/model) of the fan controller would also help.

The following shows a typical fan and controller wiring setup.
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.

brytell said:

Thanks jrichker. You have somewhat confirmed what i am going to do and that is what I needed, a little reassurance. I think I can get my way around wires with a voltmeter, wire, juice, electrical tape, and some solder. LOL –JK- I have a bsee degree with analog and digital emphases.

Im going to run a wire from vpwr to my electrical stat. Then a wire from the elect. stat. to a relay that is connected to the battery and the fan. Cant get any simpler than that. I would draw a pic of my schematic and post it, but I don’t know how.

Click to expand...

Microsoft Visio is a great tool for creating circuit diagrams.

Since you have a BSEE, you migh be interested in the prototype PWM controller I designed. PM or Email me your email address and I will send you the circuit diagrams and the bill of materials.