A/C blower motor won't work when it's hot Inside the vehicle

2016 sr5
Now that it's getting warmer out I've started having an issue where the blower fan will not work when it's gotten super hot inside the car. If I take it off recirculate, cold air still gets forced through the system and eventually the blower kicks on after about 10 min of highway driving. Still gets very cold but the blower seems to lose and get power surges at this point. I'm assuming it's an electrical issue or something is overheated but Im hoping y'all will have some suggestions on where to start as I'm learning to work on it as I go.

 

Sounds like the blower motor resistor is dead. It's in the airstream of the blower box for cooling.

 

It could also be the servo motor

 

What is the servo motor if you don't mind me asking? After some research I was leaning towards the resistor.

 

Not sure if this is related but I had the fan motor go out in my G1 Tacoma. It would run if I turned off recirculation and on the highway to get the fan spinning. Almost like it needed some air to get the fan going and then it would work.

 

This is coming from my experience in the Jeep world and other motors. So take it for what it's worth.

When the blower motor eventually comes on, does it work at any speed? If so, I doubt it's the resistor.

Also if the motor starts to work after it spins a bit ( from air being forced thru it), then it sounds like the brushes are worn on the motor.

I'd put my money on the blower motor itself or a loose / corroded connector.

I haven't dug into the 4runners blower motor circuit but reseat all the connectors and check the wires for damage. If not. I'm guessing it's the blower motor itself

 

A multimeter is your friend. Or, you could just beat on the blower motor when it acts up. I'm going with Tex's answer: likely the blower.