Hyundai Repair: air conditioning/blower, sonata 6, thermal expansion and contraction

Question
I own a 2001 Hyundai Sonata 6 cylinder that my blower works in the morning (air conditioner) however once I make a few stops, the blower will not work. I have changed the fuses under the dash. Is there a separte fuse in the engine that would need replacing?

Answer
Hi, Scott.  Since we know the blower will work again in the morning, we can eliminate fuses as possible causes.  Once a fuse blows (opening the power circuit) the devices it controls will no longer operate until the fuse is replaced.

Since this seems to be a temperature dependent issue, my primary suspicion is that the brushes in your blower motor are worn and making contact only at certain temperatures due to thermal expansion and contraction.  To check this, wait until the blower stops working.  Then, unplug the blower motor and install a test lamp (or voltmeter) in the connector: one lead in one terminal and the other lead in the other terminal.  If the lamp illuminates (or the voltmeter reads battery voltage), you've just verified that everything in the circuit is operating normally except the blower motor itself.  If this is the case, you'll need to replace the blower motor.