Hyundai Repair: 2000 elantra rad fan, pep boys, poor fan

Question
Greetings HT
I recently changed the rad fan on my sisters car.
it failed the same day, I checked the output from the harness wire(for the rad fan) at idle it was about 14.8 v did not check it under higher rpms
I suspect the old fan has been out for ages, I know I can get a replacement for free from Pep Boys, but

MY Questions is, how do I determine if it was just bad luck (happened to get a faulty/poor fan motor) or is there something that is causing the fans to blow
this is the fan on the drivers side, the more traditional fan motor (that looks a bit like a coffee can, not the thin one)
I don't want to just keep replacing the fan motor if there is another problem, we don't live close to each other
much appreciated

Thanks

Answer
Hi, Liam.  The only thing that can cause the fan motor to go by is if there's a problem with the fan blade turning, either by somehow hitting another object or by being out of balance.

Additionally, having power isn't sufficient.  You also need ground.  The easiest way to confirm both is to install a test light in place of the fan motor.  If the lamp lights to normal brightness, then you know you have proper power and ground.  You can make a similar test with a voltmeter, but it's impedance is high enough that you could potentially receive an improper good result if there's a poor contact in the circuit.  To avoid this, tap the voltmeter directly into the wires going to the fan motor while the motor is still connected; this way the fan will keep enough of a load on the circuit to uncover a poor contact.  In fact, you can use the test lamp in this manner, too.