i turn on the defroster it works always. but when i turn on the air or heat it doesn't always come on, sometimes it does sometimes it doesn't. but i can feel the heat or air just no blower working. any help would be great.

Hey I am not really sure about what the older model heating systems look like but if there are any lose grounds or wires/wire clips that might be affecting this. I need more info to help more good luck