Fan fuse causes drain on battery?

This mystery continues. The latest diagnosis is that there's a fuse, maybe blue in color and the car owner told me it was blue. When th is fuse is removed or put back in there's a fan that comes on when the engine is not running. I thought we had established that this fan auto comes on to cool the engine that has been turned off. A thermostat causes the fan to turn off. The car owner swears that one day the car started. Then the next day it would not and AAA and one other person think it is some fuse. The car is being towed to the same mechanic it visited last month. I personally know that the battery is not fully charged and only 385cca. These people are trying to cure a battery drain with a battery that is not fully charged. My idea which is not being accepted is to take the damn battery to Autozone for a free overnight charge to get the battery which is less than a year old to be as close to one hundred per cent as possible. Then monitor these out of nowhere the car won't start. 1990 Honda Accord. This suspected fuse related drawn downs only started this year the car has been in the hands of this owner for 15 years.
They keep getting AAA to replace batteries. No one should need a new battery every year. Who has an idea about this fuse and fan diagnosis

Batteries tent to get drained

Normally this fan will run from about 5 to 10 minutes after the car has been turned off. It is controlled by a thermostatic switch that when the engine coolant gets cool enough it shuts off the fan! If after that time the fan is still running, then my money is on a defective thermo-switch that is suppose to turn the fan off!

The fuse isn't "shorted" the fuse prevents a short or an overload to that circuit! Someone is pulling the fuse that powers the fan in order to turn off the fan before it can complete it's cooling down cycle. I agree with you, you need a fully charged battery for this to occur. But the fan should turn off by itself within a 10 minute time frame! If not, then I would take a look at the thermo-switch.

Rather than relying on poor info from the owner, you need to look at the fuse diagram to see what covers what circuit

The point about car batteries is, when deeply discharged, they are basically dead. You can never recharge a lead-acid battery that once has been dead to full capacity, and replacing it by another formerly dead lead-acid just makes no sense.

If there's some fan running with the ignition off, it's the wiring, and it should be somewhere near the fuse box. Some wire makes contact with some wire it shouldn't. I'd also check the ignition lock, maybe there's some metal debris in it that shortcuts the "off" position to "ignition on".

Actually some cars tend to need a new battery every single year. My wife's old Dodge Neon was that way. So we would just replace it every 11 to 14 months.