ESP8266 - PULLUP resistor using Arduino code

Question

I'm having some trouble with this ESP8266, to switch UP, DOWN, OFF dual relay, using Arduino code and a physical 3 states switch.

The code defines input GPIOs 12,14 as INPUT_PULLUP to avoid cases that from time to time ( say once a day ), I get a phenomena that is typically for not using a pull-up resistor.

What can cause such a thing? Can it be that GPIO12, GPIO14 does not HAVE a pull-up resistor on-board?

Relevant code (that defines inputs and outputs):

void setup() {

        Serial.begin(9600);

        pinMode(switchUpPin, INPUT_PULLUP);
        pinMode(switchDownPin, INPUT_PULLUP);
        pinMode(relayUpPin, OUTPUT);
        pinMode(relayDownPin, OUTPUT);

        digitalWrite(relayUpPin,HIGH);
        digitalWrite(relayDownPin,HIGH);

Answer 1

No, GPIO12 and GPIO14 have internal pull-up resistors (see table below). If they are properly setup in software I would suggest looking at the output (relay control circuit). Since you provided no information about the relay or how you control it I can't give a better answer.

Table from here

Answer 2

The NodeMcu has no pull-up on pins 12 and 14. The esp8266 has internal pull-up and you activate it with pin mode INPUT_PULLUP. Without activated internall pull-up, there is no pull-up for this pns.