Hard Wiring Fan Motor

[BryAZ]

My cooling fan motor does not kick on when it's supposed to. I confirmed that the motor works by jumping it to the battery. I'm guessing I have a bad temp. sensor or something along those lines. But I would rather not try to chase gremlins and just run it directly to the battery and tap into the ignition so it runs whenever the car does. Does anyone have advice for the easiest, quickest and cheapest way to do this. Where do I tap into the ignition wire(s)? Do I have to run wire through the firewall? Never done this before, so any advice would be appreciated.

[NY eric]

safe way.

Get a 12v 20amp toggle switch and a 15 amp inline fuse and some primary wire 12-14 gauge. Run one wire from the pos of the bat to fuse then to the fan then from the fan through the fire wall to your switch then to ground. Then turn it on and off at your leisure.

Not sure where to hook into the coil

[90lx86svo]

Your fan control modulel under the dash is probably fried.
Do not hook the wire up to your coil power supply.

[SVOeric]

or get one of the aftermarket fan controlers -- Like the one from SVPU.

[AT6svo]

Running the fan using a manual toggle switch is fine, however, you DO NOT want the current draw of the fan to be running into the cabin.

Use a relay mounted near the fan/battery. The switch activates the relay, eliminating the current draw into the cabin. This is what I have done on my 84 and my previous 86.

Typically the fan draws about 20A and even more at startup (of the fan). I can draw you up a quick schematic if you'd like.

[jef855svo]

Originally posted by AT6svo
Running the fan using a manual toggle switch is fine, however, you DO NOT want the current draw of the fan to be running into the cabin.

Use a relay mounted near the fan/battery. The switch activates the relay, eliminating the current draw into the cabin. This is what I have done on my 84 and my previous 86.

Typically the fan draws about 20A and even more at startup (of the fan). I can draw you up a quick schematic if you'd like.

Can you please draw the schematic you mentioned above. I have the same problem. Thanks

[AT6svo]

This is crude but should get the point across.

The switch you can find at Radio Shack or digikey, the relay, Autozone or Napa, I got mine from Off Road Warehouse. DO use a fairly large gauge wire for the battery to relay to fan to gnd connections as that is the high current path.

HTH,

[AT6svo]

Thats wierd, the attachment isnt working.

I'll try it again.

WTF? Does it not upload correctly or what? Works & views fine on my PC till I upload it, then its just the red X of deth.

PM your email addr & I can send it that way.

[SVOeric]

you posted empty html pages -- no pics.

[AT6svo]

Ok, lets give this a try....

edit: Ok, now were talking. User error

[caroth]

Try this page

http://rothfam.com/svo/fanswitch.htm

[diesel]

what about using a switch to jump a ground to the control wire on the fan controller. it uses the factory fan relay. the same thing the ecu does when the temp sensor gets to the "hot" position. a yellow wire if i remember(dont quote me on this). i would have to look. or does that make the ecu think the engine is overheating? i did it to my 86 to have better control of the fan. it doesnt overheat but i dont like where the factory setting engages the fan.

[turbizzy]

I agree, i think it would be easiest to take the fan switch wire and splice into it to a switch, then to ground. This way you can control the fan with all the factory wiring and if you forget to turn on the fan, the switch (if it works) will turn on the fan.

[jef855svo]

Originally posted by turbizzy
I agree, i think it would be easiest to take the fan switch wire and splice into it to a switch, then to ground. This way you can control the fan with all the factory wiring and if you forget to turn on the fan, the switch (if it works) will turn on the fan.

How would this actually be wired? Can someone who has done this give us a step by step. According to the previous post, the hot wire in the control module is #8 and the fan wire is #5. Where would the switch go? Thanks.

[SVOBart]

Originally posted by jef855svo
How would this actually be wired? Can someone who has done this give us a step by step. According to the previous post, the hot wire in the control module is #8 and the fan wire is #5. Where would the switch go? Thanks.

Put the switch in parallel with the temperature switch that is marked as the yellow wire with red stripe in the diagram provided in the link above. Splice one of the switch leads into the yellow/red wire, and ground the other.

I've attached a modified wiring diagram of how I've hooked up a manual fan switch and relay to my cooling fan. This design isolates the factory fan controller from the load of the cooling fan. Instead, the fan controller only turns the relay on and off, which is the way Ford should have designed the circuit in the first place. I splice the relay into the existing power lead to the fan ahead of the factory connection to maintain a stock look and to minimize the amount of additional wiring required. You don't have to do anything to the existing ground lead from the fan, but you will have to wire a ground from the relay to the nearest available chassis ground. I have the relay on my car located right next to the battery on the inner fender to minimize the length of wiring needed to and from the relay. Make sure to heat shrink the spade terminals since it will be exposed to the elements.