RepairPal Certified shops can diagnose and repair your 1990 Ford Aerostar. They provide transparent pricing with a minimum 12-month or 12,000-mile warranty on repairs and services.
if the fan isnt working at all then check for power going to the blower motor if there is power there then you will need a new motor if there is no power there then check the blower resistor
Dont forget to check for a proper ground also