HV battery cooling fan

I have a suspect failing HV battery in my just acquired ‘08. It’s my 4th gen2 purchased in last year and though the other 3 had 200-260k miles this 169k is first to cause concern with hybrid battery. Admitted I’ve learned little about Prius still and my confusion is why the battery cooling fan won’t turn on even after driving considerable time with the red triangle on? Fan is clean and works with direct current and fuse is good, but no power at its plug even with battery casing considerably hot to touch. Can a failing battery cause the fan not to turn on? I read there’s no fan relay but it’s triggering is internal with the battery ECU.
Onboard diagnostics shows blue bars cycling between 2-7 bars with occasional 7 green. ICE seems to run fulltime, even parked or at stoplights.
Any feedback is greatly appreciated, thanks.