I know with the factory fan cluch there are a lot of variables for the fan to
come on. Does anyone know at what temps Coolant/oil/ trans that would
make the fan come on?? Or does anyone have the wiring diagram of where to look to see if it is unplugged?? Thanks ahead for any input!!!

 

Well it's variable. Locks in at 100% at about 218 ECT IIRC. Somewhere near there.

It plugs in on the drivers side of the engine, right at the stator assembly. The wiring to the fan is tough to see with the stator and fan shroud in there...

 

This is from the tech folder (thanks Bismic!)
Some say fan kicks on at 210, some say 215, others say 220. Full explanation: Engine temperature is not the only parameter that the PCM monitors to determine cooling fan operation. This is the reason that you will see some variation in engine temperature as it correlates to fan operation. The operation/description of the FSS (Fan Speed Sensor) from the PC/ED manual has a fairly good explanation as to how the system "thinks". This is not your traditional engine hits temp X and the fan clutch locks up. The fan speed sensor is a Hall-Effect sensor integral to the vistronic drive fan (VDF). The powertrain control module (PCM) will monitor sensor inputs and control the VDF speed based upon engine coolant temperature (ECT), transmission fluid temperature (TFT) and intake air temperature (IAT) requirements. When an increase in fan speed for vehicle cooling is requested, the PCM will monitor the FSS signal and output the required pulse width modulated (PWM) signal to a fluid port valve within the VDF. Engine begins to defuel at 221 deg. The thermostat begins to open at about 190*F to 195*F and is not fully open until about 215*F to 219*F..

 

There is a plug just outside of the shroud on top just in front of the upper fuel filter. Check inside the shroud below that connector if you think you may have a broken wire. Fan sometimes likes to chew on it if it's not properly secured.

 

Well you can program the SGII for Fan RPM and watch what its doing

FSS Fan Speed Sensor (RPM) TXD: 07E022099F RXF: 04620509069F RXD: 3010 MTH: 000100040000 NAM: FSS

Like David Says it comes on at 218* but Mine only hits 1500RPM then and IIRC it hits upto 3000RPM IIRC not 100% shure on this MAX speed thing though

If your fan was unplugged the truck wouldnt start is that your problem or?????

Fan speed is controlled by
Speed
Ambeint temp
ECT
A/C compressor On
things like that you would have to watch it for a Few to get a Feel for it

 

Mine seems to be on at all times. Guessing it is time for a new fan clutch?

 

so you can hear fan howel all the time?????????

 

Where do you see this stated officially Benny?? A set number at which the fan comes on is contrary to what the manuals say .............

 

if ur fan howls all the time, it may be something else that is causing it to come on and stay on all the time. not to sounds paranoid, but maybe something within the entire cooling system is going out, and the car's temp sensor is not detecting stuff tat are being cooled properly, and so it keeps the fan going constantly to keep the entire engine cooled.

maybe ur engine system is throwing up more heat than normal, which would again suggest something is not being cooled properly, and something may be going out or something has already gone out. i'd look into that so as to be able to catch the problem early.

 

Some of these temps are just what I noticed with my truck not from manual.

The FAN has several trigger points all of which is a SET Number. IMO they Have to be certain set temps to make it work to step the fan rpm up



I mention 218* ECT cause Most trucks will engauge the FAN by/at this point. I have heard anything from 210*-215*-218* ECT at this point the fan will usually kick upto 1500+RPM. Trigger points are slightly diff year to year or really what Stratigy the PCM is using.

another example would be like 95* Ambeint temp A/C on and stoped at a traffic light would kick my fan rpm upto 800+rpm again just what I noticed with my personal truck

 

I believe what Rusty posted is correct. The PCM looks at a variety of parameters to operate the fan - not any single set temperature, and sends a duty cycle comand to the clutch. Not sure why you say there has to be set temperatures. Do you have a copy of the PC/ED manual? It has been awhile since I looked it over.

 

When I start the truck in the morning, delta is 2*. Let it warm up for a bit and start driving, coolant temp rises faster. Both stay within 15* coolant levels off at 192, oil about 5 to 7* warmer once it gets there. But fan is always on. No EGR to worry about either.

 

Your saying after a cold soak (12+ hours) your still seeing a 2F delta between EOT and ECT? Sounds like you've got a bum sensor. They should be the same after stilling that long.

 

Hey Crash, can you describe what you mean by "fan is on"? Not trying to be a smart*** but I've never seen mine off with truck running. Have you ever heard it kick in to high gear, maybe pullin a load up a hill on a hot day? It sounds like someone's trying to pass. Is it like that? Or maybe a medium speed?

 

Well, once I hit 3rd, I can really hear much. (4in straight pipe, powermaxx, and Windows always down. But I hear it until third, and every downshift. Even a rev in neutral I can hear it. I unplugged the EGR valve just to see if it would cut off. But no luck. Still doing the same thing.