Heater fan making noise(sometimes)

Here's the problem:sometimes my heater fan makes a noise like there's a card stuck in it then it quits for a while(93 3.0).Also it doesn't put the air that it was through the vents,but seemed to pick up though when I changed the battery and I haven't heard the noise since.Coincidence.This Aerostar has around 142k.

Here's the problem:sometimes my heater fan makes a noise like there's a card stuck in it then it quits for a while(93 3.0).Also it doesn't put the air that it was through the vents,but seemed to pick up though when I changed the battery and I haven't heard the noise since.Coincidence.This Aerostar has around 142k.

it was probably a leaf or little debri in the cage or got up under hood i would't worry about it you'll know when it's the motor.