AC will not come out the dash vents all the time. Can lower the fan speed really low and they will sometimes switch back to the dash. All air is coming out the defrost vent.

Douglass, Your A/C may have lost it's programming, blend door actuator could be faulty or A/C could be low on refrigerant. You may have to take in and have a good Tech. diagnose and estimate repair.
Check the attached links,instruction and guides, Good luck
"I hope this helped you out, if so let me know by pressing the helpful button. Check out some of my other posts if you need more tips and info."
Dual climate controls drivers side hot passengers side cold have 2004...
hot on driver side
Drivers side vents will blow hot air while is turned on but passenger side...

First check all the fuses. There should be one for Blower or Heater. If all fuses are good, It is likely a bad blower motor or a switch to turn on the blower motor. Try all fan speeds in non auto mode and see if you get any activity. If you get activity on some fan speeds then it is the switch or sometimes called the blower motor resistor. If no activity, its time for a new blower motor. They are under the dash usually on the passenger side, shouldnt be too hard to pull out.

sounds like blower bearings are dried out and will eventually lock up the blower..sometimes you can spray wd40 in the blower bearings and it will work fine for a while.. also check vacuum controls to the baffle dors in the ductwork..may have some leaks there.. should hear a slight hissing if really bad..repost findings

replace blower motor resister

common for the 4WD switch it self to go bad, what happens is the connection in the switch solider goes bad from the heat and current draw from the light. Inspect the switch and repair any signs of damage or replace the switch in the dash.
Below are normal car AC pressure readings with 134A.

• Normal readings on high and low side with AC OFF (static pressure) – Depends on outside temperature, but normally is between 80-105 PSI
• Normal low side reading with AC on high speed and MAX & engine at 800-1000 RPM’s – Ranges from 25-35 PSI
• Normal high side reading ranges from 200-350 PSI

Don’t assume that if adding little Freon is good that adding a lot is better! Overcharging just a little can decrease the performance of the system and possibly damage the compressor

BOTH readings should be checked to have a better idea of what is going on with an AC system but based on the limited information… the compressor is not engaged or is not pumping. Below are some things I would check;


1. Check the high and low gauge readings with the AC on & set on MAX/Recirculate, middle vents with the engine at 2,000 RPM’s, blower speed on high.


2. Check the vent temperatures with a thermometer from the middle vents, far right & far left vents?


3. What is the outside temperature at the time the readings were taken?


4. Check to see if the condenser fan blowing strong?


5. Notice if compressor clutch is cylcling excessively.


Thank you for using fixya and be safe

The 1992 was prior to Buick putting cabin air filters in so there is not a possibility it is clogged. So more than likely your blower motor is going bad or your fan control switch is bad. Does this problem occur with heating as well as AC? Does it change if you switch between blowing on floor, face, window(defrost) If it doesnt change based on location of blow and type of air temp then I would start by turning fan on high and placing head (ear ) against dash in center of console area. Have someone turn fan knob from low to high with engine OFF...After goign from low to high and back a few times you can see if the blower motor is responding to signal from switch. Listen for a whine, squeal, rattle, or humm. A whine or Humm would indicate a bad blower motor... Squeal or rattle a bad squirrel cage/fan blower blades. If you hear no noise and no perceivable change in blower speed/noise then its possible your switch is bad. Unfortunately the only way to definitely diagnose either is to pull the switch from dash and use multimeter to test for voltage change and for blower motor to pull dash. There is a digital control unit for your car as well. Although rare sometimes the wires on this can loosen or it can go bad. But since you didnt state teh fan wasnt working at all and you are getting cool air, that woudl be teh last thing to check

this is because you have a bad switch which has gone bad and you need to replace it or either try to bypass it through another circuit.

i assume u r refering to the cooling fans,,, if this is so the freon is low ,fans come on and lower the high side ,there fore lowering the low side and the low side switch cuts it off and on,,charge it up

No obvious reason for this behavior, so it is likely the control head is failing. You may be able to get a used one at a salvage yard.