Should I be able to hear my HV cooling fan?

No generally you cannot hear it you could put a auxiliary microphone back there possibly and see what you can make happen but it works generally That's not a real heavy blowout item not much to it It doesn't run as much as your blower motor does for your AC or heat If you maintain a decent cabin temperature in the summer like with your air conditioner your fan doesn't run that much because it's nice and cool in the cabin it's getting pumped back there to wear your battery is due it's a natural flow through type system

 

Again, on the lowest couple of speeds (1 or 2), I can't hear it. Maybe by 3 if I listen for it while the car is stopped. Definitely 5 or 6 (highest).

 

if you can hear your hv battery fan then something is wrong (or impending doom) with the battery. When my HV battery is bad the fan will kick in at higher speed and RTOD or Replace Hybrid Battery show up as well as the check engine.

 

ive heard mine twice. both ascending in the rocky mountains ending my 12 hour one way trips there

 

I've never heard the fan on our 3rd gen, and when monitoring with ScanGauge II was seeing speeds getting up there, speed 4 IIRC. Not sure how many "steps" it has, 5 or 6?

 

Your battery is not hot because the fan runs all the time. Its running all the time in a G2 but at very low speed.

Btw, when you get the red triangle of death and you also hear the fan running on high very clearly in the back that means the hybrid battery has failed.