Had the A/C system turn all wonky on me on the way home from work. A/C got very hot and the fan speed went to full. Even pressing the OFF button for the HVAC did not turn off the interior blower motor.

Got home and did some research on the issue, turns out it was the blower motor resistor. Rockauto has them for $28+ shipping which ended up to about $38 all said and done OR Advance had the "Carquest" Brand that looks exactly like the RA ones for $41.

Bit the bullet and spent the $41 on the Advance part since today's high was 81F. Followed the video that's attached (minus using a pick for the harness, I was able to unplug it easily). The hardest part about all of this was lining up the screws for the glovebox so it's very doable for anyone who can change their 3G TL cabin filter.

Part from advance:
https://shop.advanceautoparts.com/p/...lVehicle=false

Youtube DIY Video:

My TL is just getting near 18+ years old and this was the factory blower motor resistor I replaced. In all honesty, buy one and swap it the next time you need to do a cabin filter. It's pretty straightforward and save the hassle of A/C going out when you need it. Not a bad preventive replacement if the car is 14-18 years old IMO. I'll certainly be keeping one on hand for the MDX in the future.

 

I just did the same repair on my mothers 2001 Olds Alero V6. The only speed that would function was full, lost all of the lower speeds.
Gotta have AC in the Sunshine state!

 

Same problem. Fan speed at max, no control, no cold air. Replaced Blower Motor Control Module/Resistor. $30 on Rockauto Part # SW11244C (SW-11244C)
https://www.rockauto.com/?carcode=1429130&parttype=6557