Intermittent: Blower fans not working at any speed.

You described the exact problem I was having with my 2005 taco. Dealerships when into an expensive parts replacement tour. The problem was in the wiring before the motor, which I had to find myself.

Reach down while the engine and ac/fan are on and press/wiggle the 2 wires leading into the blower motor wire harness at the blower motor. if the fan starts/stops.... The dealer sold me a second blower motor and relay which only worked for like 2 weeks so I started wiggling wire and found the 2 wires leading into the harness to be burnt crunchy. I had the parts manager look up the wires and (special part) plugs that press into and lock into the blower motor and I soldered them together and used heat shrink rubber sleeves to seal the job. That was a 10 dollar fix that has lasted 10 yrs with the original blower motor. I made them buy back the one they replaced in error

 

Im just going through this as well.
2013 taco v6. 117k mi. fan settings 1-3 non operable, 4 high on. repositioned passenger 4 pin connector and all speeds worked for 1 week.
Again fans stopped 1-3 and repositioning connector fix no longer suffice.
bought a china replacement resistor and replaced only it without changing pigtail and all settings again worked for a day. then again 1-3 stopped and re-applied repositioning techinque and all settings working again. Plan on doing pigtail as well soon when I anticipate it will fail again soon

 

use the new style plug and resistor, end of issues....

 

done, I'll see how long it works. thanks all