On the way to work today I noticed air blowing through the vents whenever I was accelerating at least a little bit even though I had the vents OFF and the fan OFF.

I'm guessing this is because my manifold vacuum isn't as high unless I'm cruising so the vacuum motor can't maintain position, but I would think there would be a 1-way valve and a reservoir tank to keep the vents in whatever setting I chose under these conditions.

Am I wrong? Is this typical?


Hey! I just looked at the TSB's and found bulletin # 95614 regarding objectionable air flow from vents under heavy acceleration. Anyone have access to this TSB?

Mine occurs with barely any acceleration - wonder if my engine is just worn out and I don't have great manifold vaccum.

TIA,
Dave
93' Ranger XLT 3.0L 5spd Regular Cab Long Bed

 

Article No. 95-6-14

FORD: 1993-1994 EXPLORER, RANGER

ISSUE
Objectionable airflow from the heater system panel
registers may occur when the system is in the OFF
mode and the vehicle is under heavy acceleration.
This condition is caused by movement of the fresh
air door when the vacuum to the door actuator is
lost during heavy acceleration or other low engine
vacuum conditions.

ACTION
Installation of a vacuum hose/reservoir/check valve
assembly will provide sufficient vacuum level to
maintain the heater system fresh air door in the
closed position. Refer to the following procedure for
service details.

SERVICE PROCEDURE
1. Remove the blower assembly from the vehicle.
2. Drill two (2) holes in the blower assembly, in a
vertical position, to allow for installation of the
vacuum reservoir.
3. Using two (2) screws (389915-S2), mount the
vacuum reservoir (F4TZ-19A566-A).
4. Disconnect the existing vacuum check valve
from the engine vacuum harness and the main
wiring harness.
5. Reinstall the blower assembly in the vehicle.
6. Attach the vacuum hose in the wire harness to
the new check valve included with the vacuum
reservoir.
7. Remove the inline connector to the “T” in the
engine vacuum harness.
8. Attach the check valve to the engine vacuum
harness with the vacuum hose and inline
connector provided on the assembly.
9. Start the engine and verify proper operation of
the Fresh Air/Off door.

PART NUMBER / PART NAME
F4TZ-19A566-A / Vacuum Reservoir Assembly
389915-S2 / Screw

 

Thanks so much!!!

Next question - are TSB's just a guidance for the dealer on how to fix issues, but because they are not recalls they are not done free?
Suppose I could just go to a junkyard and get a reservoir from any car that has one and use it.

 

TSB's are for guidance, but if the vehicle is under warranty then the work is covered 99% of the time.

You might initially consider adding another, or replacing the existing, check valve itself before going the TSB/reservoir tank route. See what happens.