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If you'll find out what's making it run all the time and fix it the PCM does quite well at running the fan correctly.
Yeah. I think it would be a lot better if I could turn it on before I tow a giant hill and keep temps down instead of towing half way up it and then it kicking on when my ECT hits 218-220
What would be Great it to be able to SPeed it up AND Slow IT DOWN
03 kicks the Fan in To Late @ Summer Like 218*f then it goes to 1500+rpm Sure they try use the thermostat to Full Advantage But @ 215* F ECT it should Kick In IMO Maybe Ramp to 800-1000fan rpm @ ECT of 212*f
Stay away from Defuel temps more Summer
In Winter Theres No Reason My FAN is Kicking @ 400- 500rpm AT 20*f Ambeint With ECT STUCK at 130-140*f at the Drive thru and Wont warm up Fast Im thinking Better MPG Slower its got to Push FAN RPM anyways I think with the Proper Fan Shroud it Moves Lots of AIr Around the Engine as well
The Fan don't need to Kick in til 190*f ECT as well in winter
I think my Fan Control SUCKS for Programing in 2003 that a Later Flash may Help
with Longer GP Timer in Winter Keep the Pigtail Light on 60+ seconds before Start Maybe 45 seconds I got to Watch it more to decide
Can you See I have a lot of Demands LOL
I been thinking Custom Tunner
Anyone think there would be HARSH EFECTS on the Fan Clutch with any Senereo??
Could a good tune writer change the fan operational parameters?
I'd love to see the fan work less in the winter and more aggressively in the summer.
Having the truck that would reach operating temps quicker in the winter, and possibly get better winter MPGs, would be nice for those of us who have a short work commute.
As David pointed out the PCM uses multiple parameters to control the fan in order to optimize engine cooling. I think I would let the computer do it's job and not try to control it manually. Also remember this is not a standard fan clutch so if you do decide to try manual control I would really understand this circuit before I "rigged up" something. The fan is controlled by a visitronic drive which operates from a 12v PWM signal from the PCM. The PWM signal controls the on-off time of a valve (via a relay) which determines the fan speed. There is also a Hall Effect speed sensor which supplies feedback to the PCM. How does the PCM programming respond to the speed sensor feedback when the fan isn't supposed to be operating?
If I were to lift the output of the PCM, ( pin 14, I believe)and insert a commercial (of Chinese descent) adjustable PWM providing input to the fan, how would the PCM respond to detecting the fan is not turning at the speed it "thinks" it should be? Appropriately wired through a double pole switch, I could allow for manual control when climbing hills with a load, and under normal conditions, flip the switch back for OEM PCM control. I could provide an appropriate load to the output of the PCM, so it thought it was providing input to the fan when in the manual mode...any thoughts..?
I've considered doing this and did some searching a while back. Apparently it is not uncommon for larger trucks to have this feature. To me, it makes sense to keep things from getting too hot rather than chasing it.
I've seen some info that seemed to indicate damage could be caused to the fan clutch because of the way it operates, but then you see people saying they've ran the mod for years with no problems.
Could a good tune writer change the fan operational parameters?
I'd love to see the fan work less in the winter and more aggressively in the summer.
Having the truck that would reach operating temps quicker in the winter, and possibly get better winter MPGs, would be nice for those of us who have a short work commute.
Some newer cars are able to do this with an electronic thermostat and an electronic water pump.
To answer your question, I was told the parameters for fan operation could be changed by tuning.