Hi,
You are testing the TIP122 out of circuit?
Please post a picture of you doing the Collector negative and Emitter positive test, with the DMM in Diode Test mode.
Where are you purchasing your TIP122?
I agree, sounds like its a counterfeit or its zapped.
Tom... 
The TO220 type leads are hard on the breadboard contacts. Maybe you should verify continuity?
I'm brazilian. I'm buying from an online store(Mercado Livre) where there is a seller of car accessories(GRUPO2B)
I also think it's a fake product...
I had already tested this continuity of conductors issue and they are conducting normally
I took some measurements and found this
| PROBE | PROBE | |
|---|---|---|
| POSITIVE | NEGATIVE | RESULT |
| Base | Colector | -10.75V |
| Colector | Base | 10.75V |
| Base | Emitter | 0V |
| Emissor | Base | 0V |
| Colector | Emitter | 10.73V |
| Emitter | Colector | -10.73V |
Is the TIP122's emitter connected to the 3.3V source's ground?
If the 3.3V source is a GPIO pin, is it able to source 11.87mA?
Did you connect the GPIO pin to the TIP122 base without a resistor in series?
I'm using 3.3V from ESP32(GPIO).
Yes. According to the datasheet, it is capable of up to 20mA.
In this test, I mean that I connected the 220 ohm resistor directly to the GPIO to make sure that the GPIO would be able to provide 15 mA. Through the multimeter, I came to the conclusion that it did.
Hi,
When you have the circuit connected to power an the controller, and you make the GPIO go high, please measure the GPIO to gnd voltage, then the base to gnd voltage.
Then emitter pin of the transistor to the controller gnd pin.
In both cases negative probe to gnd.
Thanks.. Tom..
GPIO -> GND = 3.29V;
Base -> GND = 3.29V;
Emitter -> GND = 3.29V;
Colector -> GND = 14V
Sounds like you have the load in the emitter circuit.
More than likely the emitter is NOT grounded !! 
Well, shows the worth of pictures and generic "schematics" found on "the web".
In all the images I sent here, the negative of the power supply and the ESP32 GND are interconnected.
Done
I took the measurements again and this was the result.
GPIO -> GND = 3.31V;
Base -> GND = 3.31V;
Emitter -> GND = 3.31V;
Colector -> GND = 12.5V
Emitter -> GND = 3.31V;
If the emitter is connected to GND and if the voltmeter negative lead is on GND, you must be measuring this incorrectly.
Problem solved... Ridiculously high resistance of this jumpe
Bad contact as well... Simple thing I hadn't thought of. Strange that I had previously tested continuity and no problem.
Thank you so much.
