Final answer:
Jackson Air Conditioning & Heating's direct mail campaign aims to remind previous customers to have their air conditioners checked before summer.
Step-by-step explanation:
The objective of Jackson Air Conditioning & Heating's direct mail campaign is to remind previous customers to have their air conditioners checked before the summer months. By sending postcards every April, Jackson aims to prompt customers to schedule maintenance and avoid potential breakdowns when they need their AC units the most.