Heater seems to be blowing backwards???????

[89 ST4NG]

I have noticed recently a blast of cold air blowing from behind my heater box into my passenger side floor. But it blows semi-warm air out all vents but there seem to be some lack of force behind it. I have no clue whats is wrong???. My uncle suggested the blower was running backwards, But I havent touched anything or messed with it in over a year when I changed the heater core...LOL. Any suggestions???????

It's an 89 LX

 

[Saleen0679]

Any chance you hooked the blower motor backwards when you did the heater core or was it working fine after the swap and suddenly get weak? Any leaks around the blower motor box? Try and get more detailed information about what's happening with the switches in their different positions and see what's changing.

 

[jrichker]

You may have some broken vacuum lines that control the airflow.



Diagram courtesy of Tmoss & Stang&2birds

See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host) for help on 88-95 wiring Mustang FAQ - Engine Information Everyone should bookmark this site.


Ignition switch wiring
http://www.veryuseful.com/mustang/tech/engine/images/IgnitionSwitchWiring.gif

Fuel, alternator, A/C and ignition wiring
http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

Complete computer, actuator & sensor wiring diagram for 88-91 Mass Air Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/88-91_5.0_EEC_Wiring_Diagram.gif

Complete computer, actuator & sensor wiring diagram for 91-93 Mass Air Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/91-93_5.0_EEC_Wiring_Diagram.gif

Complete computer, actuator & sensor wiring diagram for94-95 Mass Air Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/94-95_5.0_EEC_Wiring_Diagram.gif

Vacuum diagram 89-93 Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/mustangFoxFordVacuumDiagram.jpg

HVAC vacuum diagram
http://www.veryuseful.com/mustang/tech/engine/images/Mustang_AC_heat_vacuum_controls.gif

TFI module differences & pinout
http://www.veryuseful.com/mustang/tech/engine/images/TFI_5.0_comparison.gif

Fuse box layout
http://www.veryuseful.com/mustang/tech/engine/images/MustangFuseBox.gif

 

[89 ST4NG]

OK Thanks I will check into all that