On-going AC blower motor troubles, 2014 Mazda6
 

Hey folks! So I have a 2014 Mazda6, with about 173,000 miles (Its my wife and I's only car). Its been solid since I got it in 2015, I do a good job of staying on top of tune ups and brakes, tires, etc, but recently have finally run into its first "big" problem.
A year or so ago, the AC wouldn't blow occassionally. Then it got worse. Then I figured out taking off the lower passenger side panel and tapping the blower motor would get it running. Well 6 months ago that finally stopped working. I took it to a shop who wanted to charge me $990 to replace the blower motor and resistor. the panel was already open, they are right there. I could do it myself in 5 minutes so I told them no thanks. Ordered a new Blower motor and Blower motor resistor from my reliable parts shop, and replaced them. Problem solved.
Well a month ago the exact same symptoms began, and again, tapping the blower motor would make it work. But this time, a few new symptoms were added in. The air would sometimes slow down and stop completely when I braked for a red light, then start blowing full again after I accelerated. Well today it died for good again, nothing works to get the air blowing. I took out the 6 month new blower motor and resistor, they look fine (My old resistor was visibly burned).
Should I try to check for warranty's on my new 6 month old parts? The extra symptoms worries me about electrical issues. I can't spend 1k+ on this car at a shop, but if the issue is deeper I could be in trouble.

Hope that wasn't too wordy. Thanks in advance for any advice everyone!

Definitely try the warranty. Also hook up a voltmeter and see what the voltage to the motor is when braking and accelerating.

Update! The connector that plugs into the bottom of the blower motor is messed up. The wires themselves look fine but I need to wiggle the connector and use electric tape to tape the wires to the edge of the motor casing .. guessing I'll need to replace and splice a new connector to the wires but for now its working fine!

You should make this repair ASAP. Poor connection there can cause hot wires that may not have the fuse to protect the circuit. As the motor speed is adjusted higher so is the electrical load on the wires.