Auto Repair Q&A



Cooling System










Auto Repair Products

2003 Dodge Dakota heat only blows from defrost vent

there are a few causes for

there are a few causes for that problem, too many to list here, i will put togather a folder of flow charts, pics and related info and send it to a email ad if you like, let me know, mws919

there is a vaccum hose which

there is a vaccum hose which runs from the engine throught the firewall, which control the switching mechanism for the vents. Check this vacuum hose to be sure it's not broken or disconnected.

also there is a vacuum connector above the gas pedal, whcih if disconnected will stop the switching mechanism form working.

on this hvac unit it's all

on this hvac unit it's all eletronic and will have codes stored in the control module, that would be the place to start diag.
we've been having some problems with the blen doors braking the pivet shafts, and that will also set a code for door out of range.
like i said you'll need to get it scanned, but it can be insp. for any broken componets if you know where to look.
so, if you like i can send you some info on what too look for, let me know.

There are four mode doors one defrost/demist door, one floor door and two panel doors. All mode doors are driven by one mode actuator that is attached to a mode cam. Each panel door is driven via a linkage to the panel door shaft. The panel door shaft is connected to two panel levers that are interconnected and driven by the mode cam. The floor door is driven by a floor door shaft that is attached to a lever that is driven by the mode cam. The defrost door has a lever that is connected to the mode cam with a linkage. All mode doors are serviced as part of the HVAC housing and are not available as separate components.

Check the actuators onthe

Check the actuators onthe system to be sue that they are moving when you set the heat to vent or floor.



Any luck yet?

Any luck yet?