When do your twin-cooled radiator fans kick in?
Club Member
Joined: Apr 2013
Posts: 7,675
Likes: 8,401
From: Utah
Yes, turn your bike on, don't start it, and roll the throttle half way and hold it. Takes a few seconds and the pump and both fans should come on. Put your hand down by the vents, it does push a little air.
Seasoned HDF Member
Joined: Apr 2015
Posts: 10,032
Likes: 5,306
Until I read this thread, I wasn't aware what the temperature settings were for the sensor to bring on the fans. What I am aware of is that during the last heat spell (July & August) when the highs were in the middle to upper 90s, I was never aware the fans came on while stopped in traffic. At least, I never heard them. However, when I pulled up to my garage, got off to open the door, pulled into the garage and shut off the engine, the fans would be on. They would stop running about 20-30 seconds after I shut off the bike. FYI, my engine never got hot enough while stopped at a light or in traffic where I felt the need to park the bike and get off of it.
Seasoned HDF Member
Joined: Jan 2008
Posts: 5,195
Likes: 790
From: Kansas City, Missouri
They stay on till the switch is turned off. The key switch is what I use to turn it off when testing the fans. I dont think it matters about the kill switch position.
Cruiser
Joined: Aug 2011
Posts: 229
Likes: 11
From: East Iowa
Thanks for the answers guys.
What they don't get is that the temps at the head can be well past the trigger point for quite some time, but it takes over 10 minutes for the temps at the radiator sensor to get to the trigger point.
What I mean to say is, you can ride the bike on a 95 degree day, pull it into the parking lot, leave it running, check the head temps and they will be in the 235 to 245 degree range, and it will take over 10 minutes of sitting there before the fans will come on, if they ever come on. Harley says that this is normal.
What they don't get is that the temps at the head can be well past the trigger point for quite some time, but it takes over 10 minutes for the temps at the radiator sensor to get to the trigger point.
What I mean to say is, you can ride the bike on a 95 degree day, pull it into the parking lot, leave it running, check the head temps and they will be in the 235 to 245 degree range, and it will take over 10 minutes of sitting there before the fans will come on, if they ever come on. Harley says that this is normal.
Measured where, and with what??
Any temp measure anywhere or with anything other than the sensor screwed into the head is basically meaningless as far as the fans are concerned.
How is your dealer measuring the temps??
Road Master
Joined: Feb 2014
Posts: 1,240
Likes: 170
From: Wisconsin
If You previously owned a 103 air cooled,as I have.You would find that Your water cooled engine is much cooler than an air cooled engine.I tried everything to make My 2012 Limited cooler.The only thing that worked was ,trading for a "wethead".
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Cruiser
Joined: Jan 2010
Posts: 104
Likes: 19
At temps above 90 degrees or so while riding in stop and go city traffic, my fans are running although I can't actually hear them. The only way I know is to reach forward (while stopped at a light) and place my hand by the fan vent. They also run briefly when I pull into the garage on those said hot days.
Road Captain
Joined: Sep 2011
Posts: 699
Likes: 13
From: Northeast
Don't confuse head temperature with your coolant temperature. The fans cycle on and off depending on vehicle speed and COOLANT temperature. The fans and pump are controlled by your temperature switch which is mounted on your left radiator.