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Originally Posted by Neelskit
I have a 1999 LeSabre Limited with ACC. When panel vents are selected, air only blows out defrost. Also, the RECIRC doesn't appear to work either. The floor vents and heat/ac blend work. Does anyone know where to check vacuum pressure for the HVAC system?
Thanks in advance!  |
First question do you have auto dual control digital readout air conditioning?
The lack of vacuum from the engine compartment means the valves sit with defrost enabled for safety and a little air comes out the bottom at the heater openings.
TO test for vacuum inside: run the motor and push different buttons and listen to see if you can hear any of the valves changing. Then turn off the motor and immediately press different buttons to see if you can hear the valves move inside the car. You should have vacuum for about 20 seconds of that.
If you don't seem to get any response inside take off the engine cover (unscrew the tube that the oil filler screws onto-just take hold of the whole thing and twist) then look at the driver side back for a 1/8 inch black slick plastic tube coming out and going up toward the air conditioner tube in front of the passenger. If that tube's connect both places, then crawl under the front wheel in front of the wheel inside the fender there's a tank with one tube tightly slid onto it. Make sure that's there. You should be able to pull that tube off and have vacuum there when you run the motor. That tube comes from in front of the passenger where there's a "y" in the tube from the manifold--one end goes inside the car. The other goes to the storage tank in front of the wheel.
Next to the "y" there's a one-way valve for the vacuum to keep the vacuum from dropping when you open the accelerator.
Goes through these checks. If the problem is not there, then it may be inside with the programmer box that switches the vacuum. But first determine if you have vacuum at all.