Drop the glove box. Behind it there's a black cover; remove it. Once you remove the cover, you'll see the heater core. Off course, you'll have to drain some coolant and remove the two small hoses hooked to the heater inlet and outlet on the firewall. Replacing the core on a 1989 ranger is not a difficult job and shouldn't take you too long.
If you're not sure how to do it, I suggest you buy a haynes/chilton manual (probably $5, shipping included, for a used one on amazon).
Wednesday, November 19th, 2008 AT 2:22 PM