Solved: AC repairs

Showing posts with label AC repairs. Show all posts

Tuesday, May 29, 2012

2003 Ford Taurus: A/C Fan not Coming On Time?

AC blower/heater fan is running and starting up.But its not coming up on required time.

You will notice that it comes up when pressure gets too high like 320psi or 350psi or even more then that.

This is most likely a faulty ac dual pressure switch. If it fails, the fan wont come on at proper time and the compressor wont kick off when pressure gets too high, which 350psi is.

As per wiring diagrams if you see:-----
The fan operation is controlled from the pcm, when the pcm turns the ac clutch relay on it should also turn on the fan relay but isnt. The fan kicks on when high side pressure reaches more then 300psi , and in this condition compressor stays engaged as well as pressure then drops and this is not good for compressor.

The pcm gets 2 signals for fan control - one from the ect sensor and one from the dual pressure switch:---
See the wiring diagram shown below for your help:-----

ford A/C wiring diagram

So if the dual pressure switch is acting up the pcm dose not recieve a signal to trun fans on for normal operation.

If dual pressure switch is not working properly, two things happen - head pressure goes up too high as the pressure switch should cut the compressor off when pressure gets too high and fan doesnt cut on when it should to help keep the pressure lower.

And this explains that the signal to the compressor and the fans is not correct due to the dual pressure switch not functioning correctly which is causing the pressure to rise too high and your fan not to turn on until pressure is at 350.

This details will help.

Thanks.

For All types of Car models and brands help
Go to Newly Launched

FREE Car repair guide?
http://technoanswers.blogspot.in/2012/03/car-repair-guide.html

&
Complete Car repair Help FREE?

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Saturday, November 26, 2011

How to Operate Car AC ?

Follow this procedure to operate your car AC:----

To cool off your car after it has been parked in the hot sun, drive with the windows open for a few minutes. This vents the hot air, allowing the air conditioning to cool the interior more quickly.

Make sure the air intake grilles in front of the windshield are not blocked (by leaves or snow, for example).

On humid, do not blow cold air on the windshield. The windshield could fog up because of the difference in air temperature on the inside and outside of the windshield.

Keep the area under the front seats clear to allow air to circulate throughout the vehicle.

On cold days, set the fan speed to high for a minute to help clear the intake ducts of snow or moisture. This can reduce the amount of fogging on the windows.

When driving on dusty roads, close all windows. If dust thrown up b the vehicle is still drawn into the vehicle after closing the windows, it is recommended that the in intake be set to FRESH and the fan speed to any setting except "OFF".

If following another vehicle on a dusty road, or driving in windy and dusty conditions, it is recommended that the air intake be temporarily set to RECIRCULATE, which will close off the outside passage and prevent outside air and dust from entering the vehicle interior.

HEATING

For best results, set controls to;
Fan speed ---- Any setting except "OFF"
Temperature----Towards WARM (red zone)
Air intake ---- FRESH (outside air)
Air flow ---- FLOOR
Air conditioning ---- OFF

For quick heating, select recirculated air for a few minutes. To keep the windows from fogging, select fresh after the vehicle has been warmed.

Press the "A/C" button on for dehumidified heating.

Choose floor/windshield air flow to heat the voltage interior while defrosting or defogging the windshield.

AIR CONDITIONING

For best results, set controls to;

Fan speed --- Any setting except 'OFF"
Temperature --- Towards COLD (blue zone)
Air intake --- (outside air)
Air flow --- PANEL
Air conditioning --- ON

For quick cooling, move the air intake selector to recirculate for a few minutes.

VENTILATION

For best results, set controls to;

Fan speed --- Any setting except 'OFF"
Temperature --- Towards COLD (blue zone)
Air intake --- (outside air)
Air flow --- PANEL
Air conditioning --- ON

DEFOGGING

The inside of the windshield

For best results, set controls to:

Fan speed --- Any setting except 'OFF"
Temperature --- Towards WARM (red zone) to heat; COLD (blue zone) to cool
Air intake --- FRESH (outside air)
Air flow --- WINDSHIELD
Air conditioning --- ON

The outside of the windshield

For best results, set controls to:

Fan speed --- Any setting except 'OFF"
Temperature --- Towards WARM (red zone)
Air intake --- FRESH (outside air)
Air flow --- WINDSHIELD
Air conditioning --- OFF

On humid days, do not blow cold air on the windshield. The windshield could fog up because of the difference in air temperature on the inside and outside of the windshield.

DEFROSTING

The outside of the windshield

For best results, set controls to:

Fan speed --- Any setting except 'OFF"
Temperature --- Towards WARM (red zone)
Air intake --- FRESH (outside air)
Air flow --- WINDSHIELD
Air conditioning --- OFF

To heat the vehicle interior while defrosting the windshield, choose floor/windshield air flow.
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This details will help.
Thanks.
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For car AC related and Heater related solutions. You can refer the options mentioned below:---

For details regarding:--

How does Vehicles Engine cooling system works?

http://repairhelpcenter.blogspot.com/2011/11/how-does-vehicles-engine-cooling-system.html

Engine cooling components working?

http://repairhelpcenter.blogspot.com/2011/11/engine-cooling-components-working.html

How to flush cars radiator?

http://repairhelpcenter.blogspot.com/2011/11/how-to-flush-cars-radiator.html

Thursday, November 24, 2011

How to Replace Vehicles AC Expansion Valve?

If you need dis-assembly or replacement instructions for any other auto/car part, or you want to ask question related to your car/truck jeep problem then please leave the comment with your details, so I can provide you the required instructions and solutions.

The AC Expansion Valve is the component of a refrigeration system that regulates the rate of flow of refrigerant into the evaporator as governed by the action of the remote bulb-sensing tailpipe temperatures.

Before replacing AC Expansion Valve,its advisable to INSPECT & TEST the Expansion Valve.

For inspection and testing procedure.Click the link below:---

How to Inspect Vehicles A/C Expansion Valve?

http://repairhelpcenter.blogspot.com/2011/11/how-to-inspect-vehicles-ac-expansion.html

How to Test Vehicles AC Expansion Valve?

http://repairhelpcenter.blogspot.com/2011/11/how-to-test-vehicles-ac-expansion-valve.html

Once its confirmed that Valve is faulty,then proceed further to replace the Expansion valve.

To replace a standard thermostatic expansion valve (TXV):

Place the ignition switch in the OFF position.
Disconnect the battery cable.
Purge the system of refrigerant; use the proper recovery equipment.
Remove the insulation tape from the remote bulb.
Loosen the clamp to free the remote bulb.
Disconnect the external equalizer, if the TXV is so equipped.
Remove the liquid line from the inlet of the TXV.
Remove and discard the O-ring, if equipped.
Inspect the inlet screen.

If it's clogged:

Clean and replace the screen.
Install new O-rings on the liquid line fitting, if equipped.
Attach the liquid line to the TXV. Tighten to proper torque.
Reconnect the external equalizer tube, if equipped.
Position the remote bulb and secure it with a clamp.
Tape the remote bulb to prevent it from sensing ambient air.
Replace the access panels and any hardware previously removed.
Reconnect the battery.
Leak test, evacuate, and charge system with refrigerant.
Do a performance test if required.

If it is not clogged:

Place the ignition switch in the OFF position. Disconnect the battery cable. Purge the system of refrigerant; use the proper recovery equipment.
Remove the evaporator inlet fitting from the outlet of the TXV.
Remove and discard the O-ring, if equipped.
Remove the holding clamp (if provided on the TXV) and carefully lift the TXV from the evaporator.
Carefully locate the new TXV in the evaporator.
Insert new O-ring(s) on evaporator inlet, if equipped.
Attach evaporator inlet to the TXV outlet. Tighten to proper torque.
Install new O-rings on the liquid line fitting, if equipped.
Attach the liquid line to the TXV. Tighten to proper torque.
Reconnect the external equalizer tube, if equipped.
Position the remote bulb and secure it with a clamp.
Tape the remote bulb to prevent it from sensing ambient air.
Replace the access panels and any hardware previously removed.
Reconnect the battery.
Leak test, evacuate, and charge system with refrigerant.
Do a performance test if required.

To replace an H-thermostatic expansion valve:

Disconnect the wire connected to the pressure cut-out or pressure differential switch as applicable.
Remove the bolt from the line sealing plate found between the suction and liquid lines.
Carefully pull the plate from the H-valve.
Cover the line openings to prevent the intrusion of foreign matter.
Remove and discard the plate to the H-valve gasket.
Remove the two screws from the H-valve.
Remove the H-valve from the evaporator plate.
Remove and discard the H-valve to evaporator plate gasket.
Install a new H-valve with gasket.
Replace two screws. Torque to 170-230 in.-lb. (20-26N?m).
Replace the line plate to H-valve gasket.
Hold the line assembly in place and install the bolt. Torque to 170-230 in.-LB (20-26N?m).
Replace the access panels and any hardware previously removed.
Reconnect the battery.
Leak test, evacuate, and charge system with refrigerant.
Do a performance test if required.

NOTE

if the expansion valve requires replacement for any reason, replace the Receiver Dryer . it is right in front of the expansion valve and should have prevented the corrosion that ruined the expansion valve. the evaporator would fail next if the expansion valve was open.

CAUTION
Exercise extreme caution, and pay heed to every established safety practice when performing these or any automotive air-conditioning system service procedures.

Cleaning the thermostatic expansion valve:

Remove the diaphragm, the capillary, and the remote bulb assembly.
Remove the superheat adjusting screw. Count the number of turns required to remove the screw. Knowing the number of turn aids in relocating the proper position when reassembling the valve.
Remove the superheat spring and the valve seat. Remove the valve and push rod(s).
Clean the valve and all parts in clean mineral spirits. Let the parts drain and then blow them dry.
Reverse Steps 1-4 and reassemble the valve.
Check the expansion valve for maximum and minimum flow as outlined in this procedure.
If the valve fails to pass the maximum/minimum flow test, then attempt to adjust the superheat spring setting.
If the valve fails the test repeatedly, a new valve must be installed. No further repair is possible.

This details will help.

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Also if you have better understanding of other car AC cooling system parts,then it will help more to troubleshoot the problem.

Check the list below or more help.

Its always advisable to know the AC components working and testing procedure,before replacing any part.

For more details regarding cars AC components.Check out the list of links below:---