Bad fan?

[watchdog]

Tonight as I was driving to my aunt's house my temp gauge pegged. I pulled over and checked all the hoses. They were fine but my fan was not coming on. At my aunt's house I checked the fan blades, they spun freely, and then checked the plug with a volt meeter. I got 13.5 volts at the plug, key on engine off, but no fan. I think the fan motor took a dump. Am I right? I installed a new Doorman unit back in June. Advance Auto will warranty the part, I just want to make sure I have the right answer.

[SVT98t]

I have an electric fan that's on a switch. I never use it unless my temps take off. That's usually from long idling, hot temps outside, and stupid traffic. I haven't used my electric fan in weeks.
It could be your fan though. Does it turn on at all??

-ryan s

[watchdog]

That's right. No fan at all.

[Dereck]

Hi Watchdog

Cooling fan is controlled by the PCM if the gauge was reading high and the fan didn't come on but the engine wasn't overheating then could be a fault with the gauge circuit.

You should have battery voltage on the Red/Black wire at the fan and continuity to ground through the Black wire, the Red/Orange is the fan control output from the PCM.

You could check the fan works by disconnecting it, then use some jumper wires to supply power, ground and power to the control wire terminal.

I am not overly certain about a Crown Victoria but I think there are two engine temperature sensors, one for the PCM in the intake manifold and the cylinder head temperature sensor for the gauge at the front of bank 2 cylinder head under the intake.

You had better hope the CHT sensor isn't bad as you need to remove the intake to replace it.

I suppose you checked the coolant level, ETC?

Does the fan run with the A/C on?

Regards

Dereck

[watchdog]

Hey Derick,

New fan did not solve the problem. No money, got the fan on warrenty. The gauge works and the engine does run hot. I have 13.5 volts at the fan plug. Coolant is full.

The fan does not run at all.

[Dereck]

Hi Watchdog

Sorry dude I appear to have misunderstood your original post, when you said the coolant hoses were okay I took it you meant the engine temperature was normal.

If your car is overheating when driving along then you probably have more trouble than a fan not working, could be

Thermostat sticking
Water pump impeller fallen off/badly worn
Plugged radiator
Low coolant

My first move here would be to hook up a diagnostic scanner and check for fault codes, then I would try to activate the cooling fan from the scanner but I doubt you have a diagnostic scanner capable of that.

You could check the fan control wire from the PCM for continuity, also check for continuity to ground through the black wire at the fan and you could put power down the fan control wire from the PCM connector to see if the fan worked, this would verify the integrity of the wiring you could also check the coolant temperature sensor and wiring.

When you say it does not run at all you mean it also doesn't run with the A/C on, yeah?

Regards

Dereck

[watchdog]

No problem.

The car runs fine while driving, but gets hot while sitting still in traffic or idleing. It has enough coolant. I think it's the intake temp sensor. The temp guage still works but the fan will not come on even when the enging is running hot. It has power but no signal. Thanks for the advice.

[sly]

doesn't the coolant sensor for the ECM control the fan?

[Dereck]

doesn't the coolant sensor for the ECM control the fan?

Hi Slymer

Yep!

Regards

Dereck

[sly]

in that case... either the wires aren't connected good... or the sensor is crapped out open and the ecm thinks it's running cold. I've had the plastic portion of a sensor up and fall off on me once. This was on a cheby though.

[Dereck]

in that case... either the wires aren't connected good... or the sensor is crapped out open and the ecm thinks it's running cold.

Hi Slymer

If the sensor has gone open circuit then I would have expected the check engine light to come on, so I think the sensor must be reading something or teh PCM isn't giving the fan on signal or maybe the fan control wire is open but I would have also expected that to throw a check engine light.

This problem requires doing some testing of the ECT and wiring continuity or checking out the system on the diagnostic scanner.

Regards

Dereck

[sly]

point. I forget the new ECMs have provisions for checking for open circuits.

[watchdog]

I did get a check engine light but not until the engine got hot. I reset the light and drove the car some today. While moving the temp stayed down and the light did not come back on.

[Dereck]

I did get a check engine light but not until the engine got hot. I reset the light and drove the car some today. While moving the temp stayed down and the light did not come back on.

Hi

Geez why is it you only ever get half a story when some one describes what happened to thier car?

What was the fault code/codes?

Regards

Dereck

[watchdog]

Sorry Derick,

The code was temp out of range, too high.

If I understand correctly, the CHT controls the gague, and the intake sender controls the fan.