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Air Flow From Vent Is Weak

91boz on Fri July 18, 2008 3:25 AM User is offline

Year: 2002
Make: Ford
Model: E450
Refrigerant Type: R134

The airflow out of the vent for our big delivery truck is weak. The air is cool but it seems like the vent is clogged or the vent door is not opening causing restricted air flow. I can hear the fan speed increase when adjusting from 1 to 3 but the air output is low.

My question is what controls the opening of the door in the vent? Is it vacuum or solenoid controlled? I do not have a manual for this truck and was hoping someone here was familiar with the operation.

Thanks In Advance!

GM Tech on Fri July 18, 2008 7:43 AM User is offline

Weak air flow is usually a sign of plugged air flow in evaporator core- usually debris like leaves etc-- sometimes walmart bags and soccer schedules (from using recirc- and no screens)-- as long as the air all comes out the vents - none out defrost or heat ducts- then forget about doors and their controls and concentrate on clearing the airflow path just beyond blower motor- pull blower motor and inspect evap inlet face to see what is going on.

The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

91boz on Fri July 18, 2008 10:59 PM User is offline

Sorry for the blank post.
Thank You GM Tech for the speedy reply1 Do you know if the blower motor for this truck is under the glove compartment or in the dash?

bohica2xo on Sat July 19, 2008 12:12 AM User is offline

The blower motor in the E450 is located in the engine compartment. You will have better luck with removing the evaporator for cleaning in this particular vehicle.

The evaporator is accessed from the engine bay as well, and most of thr steps apply to the blower motor too.


Batttery & Battery tray
Oil filler tube support bracket (the tube swings out of the way)
Windshield washer resevoir cover & bracket (2 screws)

Recover refrigerant from system

Disconnect Accumulator & suction line
Disconnect condensor > evaporator line

Remove the little bracket at the bottom of the evaporator housing

Remove 11 screws from the evaporator housing cover. 5 of them are on the crankshaft axis, the other 6 are at 90 degrees to same.

Remove evaporator housing cover, be careful with the gasket or seal.

Remove evaporator.

Sounds worse than it really is, just make sure the vehicle is cold when you start.


"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

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