The weather has been in the low 90s lately and I've noticed when I have the a/c on and the engine is fully warmed up the engine fan will come on. I think its only when I'm in traffic, not at highway speeds, but the thing that gets me is the coolant and oil temps are staying right around 190-193 degrees. It never did this last summer or the one before. Also, if I have the a/c on coming home at night, the next morning the fan will be on after a "cold" start until I get out of my neighborhood. Is this all normal?

 

All the stuff I drive the fans come on with the A.C
It is a good trick to turn the ac on or the defrost to check if the fans are realy working .

 

What are you monitoring oil & coolant temps with?
Radiator Fan speed is also avail via odb2 port..
I guess you mean the fan is "on" loud and you can hear it? Because the fan always turns, just at different speeds typically 400-800 rpms with a/c on.
Verify coolant level and oil level..

 

I use an Edge Insight monitor. And yeah when I say its on I mean I can hear it from inside the truck. I'm not sure if the Edge can read fan speed, ill have to check next time.

 

The connector and wires to the radiator fan controller sometimes get hit by the fan blades, you might visually check because the radiator fan on high at cold start would be odd.

 

I have noticed that when I went from the standard fan to the "snow plow package" fan, the fan is more pronounce. This is because the "snow plow package" fan is turning more at a lower RPM than the standard fan.

Do you have a snow plow package fan?

 

Not that I know of

 

I have to agree, I don't notice my fan as a pronounced noise at startup even with the a/c on. But yes it does activate the electric fans on my 98 neon, any time the a/c is turned on it automatically turns the electric fans on which is concurring with other post. But I never recall hearing the roaring of the fan on my truck with just a/c only. when towing and hitting @ 220 i do. Did you unplug your egr electrical connector?

 

EGR is still plugged in. I did notice that my coolant is a little low, about 3/4" below the MIN line so I will be adding some tomorrow. I don't know if that is low enough to matter, especially since the temps were still good

 

Ian, have you read this entire link.

https://www.ford-trucks.com/forums/1...ed-sensor.html


The fan is suppose to come on when AC is turned on. The fan stays on to a certain duty cycle until 45mph and above, then the fan shuts down. Under 45mph, the fan will cycle duty on.


Here is a portion of a data log CSV file from my DashBoss.

 

Found some info in the workshop manual.


A/C Pressure Cutoff Switch — 5.4L and 6.8L

The A/C pressure cutoff switch is used to interrupt the A/C compressor operation in the event of high system discharge pressures.

• The A/C pressure cutoff switch is mounted on a Schrader valve-type fitting on the high pressure side of the A/C manifold and tube.
• A valve depressor, located inside the threaded end of the A/C pressure cutoff switch, presses on the Schrader valve stem.
• This allows the A/C pressure cutoff switch to monitor the compressor discharge pressure.
• When the compressor discharge pressure rises, the switch contacts open and the A/C request signal circuit to the PCM is interrupted. When the pressure drops, the contacts close to complete the A/C request signal circuit to the PCM. For specifications regarding operating pressure(s), refer to Section 412-00.
• It is not necessary to discharge the refrigerant system to remove the A/C pressure cutoff switch.

Dual Function Pressure Switch — 6.0L Diesel

The dual function pressure switch (DFPS) is used to interrupt A/C compressor operation in the event of high system discharge pressures.

• The dual function pressure switch is mounted on a Schrader valve-type fitting on the high pressure side of the compressor manifold and tube assembly.
• A valve depressor, located inside the threaded end of the DFPS, presses on the Schrader valve stem.
• This allows the DFPS to monitor the compressor discharge pressure.
• The DFPS has two sets of electrical contacts. One set of contacts is normally closed and is used for A/C high pressure cutoff.
• When the A/C compressor discharge pressure rises, the switch contacts open, disengaging the A/C compressor. When the compressor discharge pressure drops, the switch contacts return to the closed position, and A/C compressor operation resumes. For specifications regarding operating pressures, refer to Section 412-00.
• The second set of electrical contacts in the DFPS is used for engine cooling fan control.
• It is not necessary to recover the refrigerant to remove the DFPS.

 

Thanks for all that info lilpooh, I didn't use the a/c on the way home last night or this morning and never heard the fan so its definitely something to do with that

 

Although, I still find it strange that my truck never did this last year

 

Verify it's really A/C related...
Turn on the A/C does the fan get loud?
Turn off the A/C does the fan quite down again?
repeat once or twice.

Could be an A/C problem causing the PCM to activate the FAN?

 

Its not like that though, it comes on randomly but only when the a/c is on or sometimes if the a/c was on last time I shut down the truck.