2 MELTED blower motor resistors in 2019 TRD sport 4x4 *fixed*

resistors do fail, even ford ones does
maybe, "made in China" like a lot of cheap stuff they supply

had an aftermarket water pump fail in a year and so with ball joints, now a try to buy OEM MotorCraft parts when possible

 

Check connector at the blower motor. I’ve seen them get loose and cause this failure before in other vehicles. Eventually the connector melts badly and is a pain to fix, and it could eat up another resistor by drawing extra current. Vehicle Blower motors draw a good amount of power to begin with.

 

Toyota changed suppliers at least twice already. Your 2007 had one made by GM in Eastern Europe. They switched to Denso somewhere in 2011 after the GM bankruptcy.

Since the fan runs fine at full speed, that is unlikely to be the case. Bad solder joints happen more frequently now with lead-free solder.

@JohnnyTaco do you have automatic temp control?

 

I'll take a look tomorrow when the sun's out

 

Oic. Maybe they need to stop using resistors in blower motors?

I do not have an automatic temp control

 

Did you do a resistance check on the resistor?

If it failed and shorted then you would have essentially made a small heating element. That could generate enough heat to melt the solder and would have nothing to do with a stalled motor.

In that same aspect, a stalled motor is basically a short and will also heat the resistor a lot. With the low speed being the most resistant, it could actually protect the motor some but still act like a small heating element.

If i were you, i would find the root cause so you can determine if it will happen again.

If that motor stalls on high speed (no limiting resistor inline) then your motor becomes the heating element.

Make sure there is nothing physically stopping the motor. Open that resistor up and test the low speed resistor for shorts.

 

A soldering joint should last a lifetime but unfortunately that's not the case anymore. Ever since lead was banned as a soldering component you can expect any electronic device (radios, relays, TV remote controls, TV sets themselves etc) to suffer planned obsolescence due to this one element. Solder ain't what it used to be.

 

So the fix is to wrap the resistor in a blanket and run the fan at low speed? Oh wait that only sorta works with Xbox 360's

I agree that the newer lead free solders are not nearly as good. This is something I will watch out for as I also tend to run the blower at low speed most times.

 

Hopefully you just got a poorly soldered one from the factory and it’s not a reoccurring problem. I’ll bet that the $60 dollar Toyota part is worth it compared to a cheap aftermarket one though....Like someone else said, keep your old one and try to get reimbursed from Toyota customer care. Just blame the self-diagnosis/purchase/replacement on the COVID situation...

Could be worse though, shitty blower resistors were such a problem with all the GM trucks i’ve had that I used to keep an extra OEM one on the shelf in my shop whenever I owned one....

 

That is a cold solder joint, clean it up with alcohol, resolder should be fine.

 

I had to replace one yrs ago in my 1990 Toyota Corolla,or as I called it,the"Toyota Corroded".

 

They reimbursed me 350$ for a battery that was still good . Never know man!

 

The way the contact sprung open, I would think it's a protective device. The solder melts from overheating and the contact opens to protect the circuit. Now why it failed is another question. Too much current draw in the circuit caused by a binding fan or a high resistance contact somewhere in the circuit come to mind. It could easily be an intermittent problem. Contacts do that. It can also be a manufacturing defect and the solder connection just plain failed. The fact that the fan runs fine at high speed is a red herring. Without knowing the actual speed of the fan, you don't know if the fan+resistor+connectors are drawing more then the designed current capacity of the low speed setting.

 

Wouldn’t there be a fuse in the power circuit that would blow before any other components melt in a stall or high current situation?

 

Yep. That too.

 

Well the alternative is a small control module that uses switching / PWM to reduce fan speed. Trucks with automatic temp control use that. Haven't heard of one failing in Tacomas. However, it's $240 at the dealer and $150 at Rock Auto: https://www.rockauto.com/en/moreinfo.php?pk=8768660&cc=3441741&jsn=381

The resistor is $23 at Rock Auto, compatible with 2nd gens: https://www.rockauto.com/en/moreinfo.php?pk=4691859&cc=3441741&jsn=380

If you had to replace the resistor multiple times over the life of your truck, you'd still come out ahead...

 

The resistor is actually carried over from 2nd gens, ~2 million in circulation. Factory part has been redesigned twice, and there are 5-6 aftermarket brands priced in the $20 range. Not a big deal. Just avoid the GM part, which is known to burn due to poor pin fitment.

 

The fuse is a control device to protect the wiring. The device on the resistor is there to protect the resistor and is triggered by heat. It's possible for the resistor to heat up enough to cause the device (thermistor) to open and not blow the fuse. I've repaired a few heater fans where the resistor burned out and the fuse did not blow. None of them had this protective device though and probably just failed from heat cycling. If it was my truck, I would give the fan and fan circuit a good look over and if there is nothing obvious, call it a day. Stuff breaks.

 

Ummm so this morning the worst happened. My new resistor burned up and now it's not working again. Something is wrong with my truck.

 

I will go to the dealer today and claim warranty. Will keep you guys posted.