Testing the viscous fan clutch

timesublime

timesublime

Compression Ignition
Joined
Jun 5, 2013
Messages
73
I think that my viscous clutch is not working anymore. Is there a definitive way to test the functionality of it? I read about testing the resistance between pins 1 and 2 on the unit. Any ideas?
 
Here is one way to check if it functions:

"Locate the electronically controlled viscous fan drive connector on the fan shroud, A spark may occur when the connection to battery is made. Using a jumper wire, backprobe pin 6 of the viscous fan drive connector to battery positive. The fan drive control coil is energized to 12 volts at this time. Run the engine at 2000 RPM, with scan tool watch fan speed until the fan speed increases to 1850 RPM or more for 30 seconds. It maybe takes 15 seconds before fan speed increases."

If you don't have a scan tool to watch RPM, you can still hear the fan start moving air if it locks up.
 
I guess I should have asked what year the truck is first. That test is for a 2010-2012 Ram.
 
According to the crowd that deems itself worthy of being released from society, they suggest that you just grab the fan while it is running, with the AC on, and try to stop it. If it stops, you found a bad fan clutch. Replace and move on with life until a better opportunity arises for you test your fate.
 
I have a 2008 and noticed awhile back I don't hear the fan like I used to when towing. Also running 210 at times which is above normal for it, figured it was just hot as hell summer this yr. Interested in this
 
jesnic7 said:
According to the crowd that deems itself worthy of being released from society, they suggest that you just grab the fan while it is running, with the AC on, and try to stop it. If it stops, you found a bad fan clutch. Replace and move on with life until a better opportunity arises for you test your fate.
Click to expand...

Mine was strong enough to eat a cat last winter, guess thats good enough.
 
jesnic7 said:
According to the crowd that deems itself worthy of being released from society, they suggest that you just grab the fan while it is running, with the AC on, and try to stop it. If it stops, you found a bad fan clutch. Replace and move on with life until a better opportunity arises for you test your fate.
Click to expand...

Yeah. No. Lol. 15 hp turbine of death.
 
Turn the A/C on full blast. It should kick on and off noticeably sitting still idling.
 
My 2011.5 was awful running ac with the motor cold when new. 100 degree day, remote start, run 15 minutes and the ac would be blowing 100degrees.

Compressor cycling rapidly due to high head pressure (low flow across condenser)

Many trips and videos to local stealer, 2 fans clutches of same part number, and finally got them to replace fan clutch with a different part number (TSB didn't include my VIN, but obviously same problem)

On a cold start, regardless of ambient temp, I could hold the fan from turning with my pinky finger with ac running.

Never another issue after fan replacement.
 
Last edited:
bnold said:
My 2011.5 was awful running ac with the motor cold when new. 100 degree day, remote start, run 15 minutes and the ac would be blowing 100degrees.

Compressor cycling rapidly due to high head pressure (low flow across condenser)

Many trips and videos to local stealer, 2 fans clutches of same part number, and finally got them to replace fan clutch with a different part number (TSB didn't include my VIN, but obviously same problem)

On a cold start, regardless of ambient temp, I could hold the fan from turning with my pinky finger with ac running.

Never another issue after fan replacement.
Click to expand...

That's exactly how my 12 is. It WILL NOT blow cold until the engine is full operating temp. The compressor will cycle constantly but only for a second or two.
 
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