Originally Posted by rbabos
Originally Posted by Mr. Orange 645
Here's my (newest) dilemma. A few weeks ago, I noticed my top fan was coming on as normal when the engine got hot, but the bottom fan wasn't turning. It spun freely when I turned the blades by hand, so it wasn't frozen. I figured the motor was toast.
Ordered a used set of fans off eBay and confirmed both fans worked. Jumped them with a 9v battery and both came on as soon as powet was applied. When I did the same to the old set, only the top fan would come on. Confirmed my suspicion that the bottom fan was fried.
So I swapped out the fans. Finally got it ride today for the first time since the swap. Engine heated up sitting in traffic. Top fan came on, not the bottom. WTF.
Any idea why only one fan would come on? They both run off the same circuit, correct? If one comes on, both should come on, right? Could something be frying my bottom fan? I mean I KNOW it was working before I installed it.
If you have 12v to both, they both should run. Top fan sees more overall heat, especially when sitting still or slow moving. Test the bottom fan with external power. If it repeatedly starts, might be high resistance in the feed wire to that fan. Try jumping a second wire from the other for testing. Chances are it's also pooched and on the bench, maybe it's position made it come on. I'm sure you are pissed by now with all the extra work and end up the same as before.
It wound up being the fan again. Just a if coincidence that the replacement set I bought also had a bad lower fan. My old fan was just shot. This new (pre-owned) fan had a short in the wire. When jumping it to test it, it would fire up, but wouldn't fire up installed on the bike. Which was irritating. A 9v battery would start it, but a 12v power supply from the bike wouldn't.
After fiddling around, I could get it to kick on, then it would stop. Played with the wires, and there was a short right at the motor.
But it's all good. Between the old fans and the new ones, I had two working fan motors. Tapped out one of the working fan motors and pressed it back together in the new assembly. Boom, problem solved.
And now that I know how to pull the fans from the assemblies, I can buy brand new fan from SPAL for $70 each. No more paying $200 to Harley when one craps out.