DHT22 Sensor With Relay is not working

Board : Arduino Mega 2560
My Code
When humidity > 90 Why Relay is not working???
Sorry for my language english is not my primary language

#include <SimpleDHT.h>
int pinDHT22 = 22;
SimpleDHT22 dht22;

int FanRelay = 13;

void setup() {
Serial.begin(9600);
}

void loop() {
// start working...
Serial.println("=================================");
Serial.println("Sample DHT22...");

float temperature = 0;
float humidity = 0;
int err = SimpleDHTErrSuccess;
if ((err = dht22.read2(pinDHT22, &temperature, &humidity, NULL)) != SimpleDHTErrSuccess) {
Serial.print("Read DHT22 failed, err="); Serial.println(err);delay(2000);
return;
}

Serial.print("Status: OK");
Serial.print((float)temperature); Serial.print(" *C, ");
Serial.print((float)humidity); Serial.println(" RH%");

delay(1000);

if ((float)humidity > 75){
digitalWrite(FanRelay, HIGH);
} else{
digitalWrite(FanRelay, LOW);
}
}

You didn't use code tags when you posted. You didn't call pinMode() on FanRelay.

THX And Sorry
I'm newbie