Cooling Fans Won't Come On

[RSutton22]

First of all I want to say I am sorry if this specific issue has been addressed in another thread. I did search and read several related threads before posting this one. I am trying to help my niece with her 2001 Focus Zetec.

It only gets hot when stopped due to the fans not kicking on.

The fans will not come on even if I turn on the A/C.
I have checked both relays and they are working.
The 50A fuse is also good.
I hotwired the fans and they will run.
I checked for 12 volts at the fan plugs and no voltage.
From other posts I understand that the resistor should not play a part if the A/C is on the fans should run even if the resistor is bad, correct?

The only thing that I can think of now would be the Cylinder Head Temp Sensor. My question is if the sensor is bad would that keep the fans from running even if the A/C is on?

Any help would be greatly appreciated.

Thanks,
Rick

[Sponsor]

[Fattie]

there is a resistor type thingy on the bottom in the middle , you have to take the fans out to get to it. It is more than likely rusted away to nothing. you can find a new one here

http://www.1aauto.com/1A/RadiatorFan...FUJx4Aod9B8A7A

you may be able to find it somewhere else cheaper , but i just did a quick search.

[RSutton22]

As I already stated, the resistor is bypassed when the A/C is on if I am correct.

[amc49]

But you are NOT correct. The fans come on LOW with a/c on, which requires the resistor working. They then go to high at around 230-235 degrees or a/c hitting 270 psi on the highside. Pull the resistor connector and look for melting, common on these.

The 50A fuse is for high fan, there is a lower value (30A?) fuse for low, you've missed it. Could be blown.

Relays themselves can be working but if power not present to go into relay and command not there for power to come out then relays might as well be gone fishing.

[RSutton22]

Thanks amc49.
I thought I had read in another thread that the A/C overrode the resistor.
This vehicle doesn't have an owners manual but I found one online. Now that I know there is also a 30A fuse and where it is located I will check that in the morning.

If the 30A is good then I will check the resistor. I can do a simple continuity check on the resistor right?

[sleepyboy]

Easier to just unplug it and look. Really the damage will clearly be seen. You may also need to replace the pigtail that goes to the resistor as these can get burnt up as well. On my focus both were burnt up.

[RSutton22]

I found and checked the 30A fuse it is good.
I checked the resistor wires and they are not burned.
I pulled the resistor out and checked for continuity and it had around 16-17 ohms.

[RSutton22]

I went ahead and removed the wiring harness for the fans. The plastic wire loom was brittle from excess heat but no wires were burned. I did a continuity check on all wires and plugs and all were good.

[03FocusZX3]

Check the relays.

[RSutton22]

I already checked the relays and they are good.

I just checked for voltage at the 30A fuse with key on not running and it has no voltage.

I should get voltage to that fuse even with car not running right?

I pulled the fuse box and the wires look fine.