<p>I have a Tevo Tarantula with a MKS Base 1.5 board and dual extruders.  I am running Marlin RC8 Tevo Community build for the dual extruder, large bed and SN04 sensor.  </p>

<p>All temperature sensors work and give accurate reading but <code>E1</code> when activated runs at 100% until the overtemps kicks in and shuts down the system.  Like I said, it reads proper temperatures through the thermistor it just won’t stop at the set temperature.  I checked the MOSFET and there is no obvious scorching or bad solder joints on the MKS board.  This leads me to believe it is a mix-up in firmware but, being a bit of a newbie on this, I am still getting familiar with G-code and Marlin.</p>

<p>I have confirmed the correct board is being referenced in firmware from <code>boards.h</code> but looking at <code>configuration.h</code> I just get confused.  What I am thinking is somehow/somewhere <code>E1</code> might be referenced as a fan that is just off or on.  Anybody have ideas?</p>

I am not sure what the hardware config is for the
Tevo Tarantula
Make sure your
```
configuration.h
```
file is setup for your hardware.
The extruder defines are describe in
Conditional_LCD.h
It looks like the
configuration.h file
on GitHub is configured for a single extruder.
For example, if you have 2 hotends; but, "HOTENDS=2" is not set then the I/O will not be configured for the 2nd hotend.  I just looked at the code and if
```
HOTENDS == 1
```
then the
```
MOSFET_D_PIN
```
will be used to control FAN1 (which sounds very similar to what you are describing that you are seeing).
```
```
#if HOTENDS == 1
    #define FAN1_PIN     MOSFET_D_PIN
  #else
    #define HEATER_1_PIN MOSFET_D_PIN
  #endif
```
```