LED pin 13 not flashing properly
Well, mainly digitalWrite(pinMode, HIGH); looks suspicious. I though you called LED pin as ledPin

If you fix this, it should be working. As this one is working too, it's just simplified a little:

int ledPin = 13;
int index = 0;
const int8_t sequence[] = {1,0,1,0,1,0,1,3,1,3,1,0,2,0,1,0,1,3,1,0,2,0,1,0,1,3,2,0,2,0,2,3,3,3,1,0,2,0,2,3,2,0,2,0,2,3,1,0,2,0,1,3,1,0,2,0,1,0,1,3,2,0,1,0,1};
int arrLength     = sizeof(sequence);


void setup() {
  pinMode(ledPin, OUTPUT);
  Serial.begin(57600);
}

void loop() {
  Serial.println(String(sequence[index])+" , "+String(index));
  switch (sequence[index++]) {
    case 0: wip(); break;
    case 1: dit(); break;
    case 2: dah(); break;
    case 3: wah(); break;
  }
  if (index == arrLength) {
    index = 0;
  }
}

void dit () {
  digitalWrite(ledPin, HIGH); 
  delay(300); 
  digitalWrite(ledPin, LOW);
}

void dah () {
  digitalWrite(ledPin, HIGH); 
  delay(900); 
  digitalWrite(ledPin, LOW);
}

void wip () {
  delay(900);
}

void wah () {
  delay(2100);
}