Help! - fan clutch on manual switch info
 

Alright, so I need to put my stock clutch on a manual switch so that I can turn the fan on when I need it for pulling and towing.

The wiring diagram is attached. It's the second one from the top. 2003-2004 CTD. I tried running 12v's to all the wires except the ground with no luck. I have even tried completing the ground to a ground - no luck.


Anyone know the method to wire up the stock belt driven fan onto a switch?

Thanks!

Having fan clutch troubles??

not exactly. i'm trying to have the fan kick on when I want it to, now when the ecm feels its time.

i was thinking of installing new flex-lite fans, but the stocker flows more anyways, i just want the ability to turn it on when i need it. i've noticed on some grades or when getting hot that i don't hear it turning on any more. the clutch could be fried.

i want to see if anyone else on here knows how to wire it or who tried this. i didn't find any possible combination from the available wires to do this.

IDK if I would add a switch. Might backfeed the ground or power through a sensor or the ECM and fry all kinds of stuff or keep setting codes.

good call. but i cut all the wires to avoid this. there has to be a way to wire it directly and not even use the ECM. I can rewire everything if I can't figure it out. I'd hate to drop 500 on new fans that are less effecient for no reason. All I want is the ability to turn on/off when I want. :)

thanks bud.

That's going to be the tough part, trying to wire it so it doesn't throw codes.

5.9L DIESEL (ELECTRONICALLY CONTROLLED FAN DRIVE)
The Engine Control Module (ECM) controls the level
of engagement of the electronically controlled viscous
fan clutch by monitoring coolant temperature, intake
manifold temperature, air conditioning pressure and
transmission oil temperature. Based on cooling
requirements, the ECM sends a signal to the viscous
fan clutch to increase or decrease the fan speed.
Fan speed is monitored by the ECM. Fan speeds
above or below a calibrated threshold will set a DTC.
Circuit concerns will also set fan clutch DTC’s.

good info!

but when I cut the wires or disconnected the connector... it didn't throw any codes at all.

One other thing about a switch, it's all or nothing. So this is going to kill the fuel mileage.

agreed. but i'm not looking for fuel mileage increases. i have really large injectors and big turbos and big tires. i'm only seeing 13mpg on 740hp settings. its a competition type rig and i'd rather have it all or nothing, if you know what i mean. :w2::rocking:

it looks like you maybe need 5 volts to kick the clutch, not 12 maybe

I thought of that too. but do you think that 12volts would have caused it to go anyways? i can pull 5volts off the ecm... it would be more worthwhile if I saw a result of some kind or positive proof of how the signal tells the clutch to engage. i mean common... 5 wires for a fan clutch??? hopefully someone will chime in who knows specifically how the ecm and fan communicate and what the clutch is looking for exactly to kick it over.

if i made it... it would have two wires. positive and negative!

it has to get all the reading probably from a water and oil temp, speed probably has something to do with it, RPM...i imagine all these reading go into when the ECM kicks the fan on. Not to mention the air conditioner kicks the fan on...

Darn electronics :D

there has to be someone that knows how to kick this thing.

does the fan clutch have its own 12 or 5 volts going to it constantly??

the fan has its own 5V supply, it is needed for the sensor. Hopefully you didn't put 12V to that pin.
The 5V's are needed to supply the fan control.
The fan adjusting voltage is lower than that.

Camotanker do you have the wiring to the fan, the fan itself and the ECM? If I have access to that maybe I can help you. Doin' that crap with RADAR, Engagement control and missiles all day.:w2:

Simple reason for not throwing any codes- you cut the wires.

Maybe it is cheaper to install an additonal fan from the Junkyard, than messing up with the ECM. Thats what I would do.

To generate 5Volts is simple, you just need a 7805 IC: input with 12V,output is 5V and the connector in the middle is ground -expecting costs: 20cent?:w2:


Whoops! Just saw you poweroutput of 740hp. Impressive! Does your fan operate right know? I will be expensive if the fan won't work!!!
I wouldn't mess up the fan control at this poweroutput. Much to dangerous!


Pin 1: Could be 12V or ground? Thats the reason for the needed diagram
Pin 2: Ground
Pin 3: regulating fan voltage 0V up to 5V
Pin 4: empty
Pin 5: 5V Supply voltage
Pin 6: 12V
All connectors (excluding Pin 4)have to be supplied

Hey bud,
the good news is the fan isn't fried. I turned to HVAC to the AC settings and I hear the fan working at low rpm. So it's not jacked up. I would still like to get this on a switch if possible and I don't have any wiring diagrams. I just figured there would be a simple way to bypass the sensor or to have the sensor engage on demand.

Any thoughts? Supply 5volts to the 5volt wires?

In my opinion it should be possible. There is just the need to isolate the original wiring from the add-on switch to avoid interfere with the ECM.
The 5V voltage is very common to run those devices. The fan speed adjusting voltage seems to be lower than 5V. Usually its between OV and 5V.
I assume you want the highest fan rotation with the switch in the on position?
If so you have supply 5V to the Pin 3 sensing input.

It would be the best way to measure all voltages during use. One time with the fan off, and a second time with the fan engaged. Keep a notice on all voltages at all pins.
with that list it is very easy to apply the correct voltage to the right pin.

If you don't have a digital multimeter ask a certified electronic tech. It will be a lot cheaper than to replace the fan and the ECM.
Try to get the wiring diagram, it is very helpful to know where those cables come from.
The reason why I ask is simple. If the ECM uses digital codes, you can't simply add another volltage without causing big trouble.
:c:

Very good post! SHITTY design...just had my cable chewed up by the fan today in two places so i can't re tape the wires....@#$%^&*()_ the truck starts up fine...i thought i smelled coolant on my way home[no drips]. What would happen if i ran the truck without the wire? Oh and i removed the metal housing[from wire] a way back cause it put a hole in my radiator. I had it secured good but i changed my radiator 2 weeks ago and i guess i didn't secure it right:s:

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Well i drove the truck for a while and everything was ok! I read on another forum where someone screwed the fan to the housing permanently...what i intend to do