Fans themselves can be tested indiviually by unplugging them with any 12v source with a direct +/- connection to the wires. The cap likely popped off from a poor mechanical connection to the fill spout. Look it over closely to see how the tabs are hooking in.Hi
My rad cap popped off after flooring VRSCDX (2016 model). it appears that I haven't blown a head gasket as bike is running ok / coolant level normal again - no losses
I cannot get the fans to come on and engine does appear hot - is there a way to test run them? I proved the relay is ok.
Also is there an asy way of proving the water pump is working? just keen to check things over & understand why the cap popped.