I have a 2008 Ford Focus. The cooling fan won't turn on. Occasionally, it'd turn on for a minute and then stop completely. I have changed the thermostat housing. The cooling fan is working when I feed power straight from the battery. The fuses are OK. What could be the problem?

 

What engine do you have?
How good are you with electrical work?

 

Here is the engine. Yes, I am proficient in simple electrical work.

 

I am fairly proficient in basic electrical work.

 

I would say I am fairly proficient. I can follow electrical diagrams.

 

Yes I am proficient in electrical work. Can work with electrical diagrams. I believe this is the original engine - 2.0 4-cylinder

 

I amused incorrectly, there is only one engine option.
First I would recommend checking if there are any PCM fault codes present, if you have a scan tool that can do it a on demand self test would be best.
Here is the wiring diagram for the cooling fan, the PCM provides a ground for the relay to activate either the low or high speed fan.
For electrical work you can remove both relays and jump pins 3 & 5 to see if each fan works correctly, this will also prove out the wiring harness.

 

Thank you so much Scott for this. I tried to jumpstart the fan (there is only one fan) and it did not turn on. Apparently, the fan works when I connect I feed 12v+ from the battery. What should I do next?

 

Yes there is one fan but as you can see there is two speeds it can go. What did you do to "jumpstart" the fan. What wires did you connect the battery to at the fan.

 

I disconnected the fan from the harness. Then fed power from the battery to the purple and brown wires.