Yes , the
Refrigerant level is good , I would say the control panel is bad , or there is a problem with
HVAC Air Delivery/Temperature Control Circuit Description
The vacuum actuators move the air valves in the HVAC system (except the temperature valve). Vacuum is applied to the actuators through the mode selector in the heater A/C control assembly. The mode selector consists of a rotary vacuum switch. The rotary vacuum switch supplies vacuum to the vacuum actuators according to the operating mode selected by the driver. A small servo motor moves the air temperature actuator. The small servo motor positions the door according to the voltage level from the temperature selector in the heater A/C control assembly. The temperature selector is a potentiometer positioned by the temperature control knob on the front of the heater A/C control assembly.
Air Temperature Actuator
When the ignition switch is in the RUN position, battery voltage is applied to the air temperature actuator. The actuator receives ground at all times through the following components:
• CKT 251
• Ground G204
The temperature selector is a potentiometer with a wiper arm. The wiper arm is electrically tied to the air temperature input through CKT 733.
When the temperature selector is moved between COLD and HOT, voltage to the control input varies between 1 and 12 volts. The temperature valve motor solid state circuitry performs the following tasks:
• Looks at the control input voltage
• Moves the motor to correspond to the control input voltage
The temperature valve moves for the following reasons:
• In order to allow the air to pass through the heater core
• In order to allow the air to pass around the heater core
This control achieves the desired passenger compartment temperature.
HVAC Air Delivery System Check
Step
Action
Yes
No
1
Start the engine.
Turn the blower motor fan ON and select an air outlet mode.
Does air flow out of the selected HVAC outlet ducts?
Go to Step 3
Go to Step 2
2
Did the customer concern mention that the air discharges out the correct ducts at first, but then changes during higher engine RPM?
Go to Step 7
Go to Step 3
3
With the engine running, cycle the HVAC controls through all the modes.
Does the air come out of the selected outlet ducts?
Go to Step 18
Go to Step 4
4
With the engine running, take a vacuum reading at the manifold vacuum port that supplies vacuum to the HVAC vacuum control assembly.
Is there engine vacuum?
Go to Step 6
Go to Step 5
5
Repair the no vacuum condition.
Is the repair complete?
Go to Step 18
--
6
Take a vacuum reading at the vacuum supply line at the HVAC vacuum control assembly.
Is the vacuum reading the same as the engine vacuum?
Go to Step 11
Go to Step 8
7
Disconnect the vacuum supply line from the HVAC vacuum control assembly.
With the vacuum gauge connected to the vacuum supply line, re-start the engine and turn the engine OFF.
Does the system lose vacuum after turning OFF the engine?
Go to Step 8
Go to Step 11
8
Inspect for leaking or collapsed vacuum lines between the engine manifold vacuum port and the HVAC vacuum control assembly.
Are the vacuum lines leaking?
Go to Step 9
Go to Step 10
9
Repair or replace the collapsed or leaking vacuum line.
Is the repair complete?
Go to Step 18
--
10
Replace the vacuum reservoir tank.
Is the repair complete?
Go to Step 18
--
11
Using an external vacuum source, apply vacuum to the appropriate vacuum line at the connector to the HVAC vacuum control assembly.
Does the actuator retract?
Go to Step 17
Go to Step 12
12
Inspect for leaking or collapsed vacuum lines between the actuator and the connector to the HVAC vacuum control assembly.
Are the vacuum lines leaking?
Go to Step 9
Go to Step 13
13
Disconnect the vacuum line from the actuator.
Apply an external vacuum source to the actuator.
Did the actuator retract?
Go to Step 14
Go to Step 16
14
With the actuator disconnected, inspect the door for binding.
Does the door move freely?
Go to Step 16
Go to Step 15
15
Repair the appropriate binding door.
Is the repair complete?
Go to Step 18
--
16
Replace the appropriate vacuum actuator.
Is the repair complete?
Go to Step 18
--
17
Replace the HVAC vacuum control assembly.
Is the repair complete?
Go to Step 18
--
18
Cycle the HVAC controls through all modes to verify proper operation.
Did you correct the condition?
System OK
--
SOURCE: Air conditioner won't stay on.
Most likely it is not related to the switch. More likely is the AC system is undercharged on refrigerant. The AC system will kick in when the refrigerant pressure on the low pressure side is high enough. After the compressor runs for a few minutes, this causes the low pressure side to drop below operating range and the low psi safety switch turns off the AC system. Once it has shut off the pressures stabilizes to a level where the safety switch will let the system operate again, making you think after turning the AC switch off and on again that it might be the problem. The best way to diagnose this problem is to use a guage manifold set to monitor what the pressures in the AC system are actually operating at when this occurs.
SOURCE: 2001 chevy malibu- when car starts cooling fans do not come on but then do
your coolant temp sensor on the engine block is probably faulty, however, keep in mind that if it really isn't all that hot outside they may not need to turn on. Once you activate the A/C the fans come on automatically since they have to cool the condensor...
If your car is not overheating do not worry about it.
SOURCE: 1999 Chevy Cavalier A/C blows hot air
More likely the recharge blew a o-ring and you have a leak. When your Cavalier was blowing hot air and a recharge fixed it that means it was low on freon which lets o-rings dry out, go back to the shop and have them leak test it. They use a pressurized dye to find the problem. If it's blowing it's not the cooling fan relay, they may have meant compressor relay but I'd have a leak test done first it's not expensive and easier that chasing unknown possibilities.
SOURCE: Cool but not cold air from my ac system
It sounds simple enough that you need to recharge your A/C unit. They can stop functioning properly after winter's end especially if they were not used. You should be able to get a recharge kit from your local auto parts store. Your Suburban should use the newer R142a refrigerant.
SOURCE: 1999 chevy malibu, stalls, no restart after
I had the same problem-my check engine kept coming up with crank sensor(replaced several times- the car would run for 2 days then stall again)finally checked and replaced the wiring harness and the car ran great for awhile. Now I have a whole new problem(abs lights started coming on and the gauges all died while driving at which point the car just stopped and woulkd not restart)thinking alternator(the battery works great in another car)
123 views
Usually answered in minutes!
×