Yes, replacing the heater core should slove the problem.
i didnt know dodge made Dakota quad cabs in 89
No
Dodge Dakotas do not, and have never, had transaxles.
Drop the fuel tank, (thats where its located). pull the pump out of the tank and replace with the new one.
A 1989 Dakota has throttle body fuel injection.
Autozone web page has the Vacuum diagram for the1989 Dodge Dakota.
The engine diagram for a 1989 Dodge Dakota be can be found in the Dakota service manual. The manual is available through most auto parts, or possibly at the public library.
need vacuum system diamram for a 1989 3.9 dodge Dakota p.u.
crash into wall
In my 1989 Dodge Dakota the brake light is on fuse number13 it is a 5amp it also goes to buzzer, speed control, check engine light, anti-lock warning light, and other things page 12-19 Haynes 1987- 1993 Dodge Dakota Repair Manual
You can find a vacuum line diagram for a 1989 Dodge Dakota by checking the owner's manual. You can also find them at different auto part retail stores.