Guys, how do I check if my defogger is working fine? Di ba dapat orange yung color nun sa rear windshield but I was able to see some black color lines. Does it mean may damage na yun? Or when I turn the defogger on and the whole window heats up ok pa yun?

Also, what is the correct tire pressure in psi for cars like city. is 28 sa front at 30 sa back ok?

Hope to hear from you guys.