What is your question?
·
·
What is your question?
I have the heater on and when I turn on the defrost the AC comes on and blows cold air?
2 Replies
This is normal for most manufactures. The AC acts as a dehumidifier and can be used with the heater to give you warm dehumidified air. Have you have ever noticed that on a rainy day with a car full of passengers all the windows fog up. If you run the AC with the heat at a comfortable setting you'll notice that it reduces that amount of fog on the inside of all the windows giving you better visibility and making the car more just more comfortable. Once the front window is clear enough you can return the heat to the floor setting and leave the AC on and the windows should stay clear.
Have temperature controls tested IF you get appropriate (hot) levels of warm/hot air in the other mode settings , then the air-mix door/motor may be the issue. Reply #1 is correct also- Most cars by default , turn on the A/C with defrost 'mode'.
Thanks I will give that a try...So you think it is not an issue with the switch itself?
Which switch? Re-read BOTH replies.
What ziptie12 is saying is there are a few things you want to be aware of.. All the AC button does is control whether or not the compressor is activated or not. It is normal and programmed into the control of most car for the system to activate the AC compressor automatically when the defrost is selected. However - If you activate the defrost immediately upon starting the car when the engine is cold you would not get heat because the heat is generated by the engine coolant. Make sure the engine is warm at operation temperature you and should get heat at the floor and the face settings. Make sure you have heat in all other modes (face and floor) then move the selector to defrost and see at that point if you can still get heated air even with the AC on. If in the defrost mode you lose heated air knowing that it works in the other selections that you may have an issue with the stepper motors that actuate the flow of heated and cooled air and in the defrost mode which is completely different than the AC function being activated itself. If you don't have heat in any mode floor or face there can be a handful of issues that would cause this. Understanding how the heating system works is key. A faulty thermostat, heater control panel or the unit where the blend doors reside can all affect this. This is something that a trained mechanic may need to diagnose. Answer these questions. With the heat on and the temperature in the hot setting select the face setting, can you feel hot air blowing out of the face vents? Then select the floor setting and see if you if the hot air redirects to the floor. Without adjusting the temperature select defrost. Do you still get hot air at the top of the dash out of the from the defrost vents? Try this and let us know what happens.
Will get back to you soon as I can try these options. Note, I do get hot air without turning on the fan and then when the fan is turned on that is when the AC light goes on and cold air come at all settings for direction.
You want to have the fan on when you test this. You can try this with and without the AC activated to see if anything changes. Most important... can you get hot air blowing out any of the vents? Something else to add. Look at the temperature gauge on the dash after driving for about 15 to 20 minutes. Where does the temperature gauge read? Is it in the middle? Does it stay close to the cold notch? Is your yellow engine malfunction light on while you're driving? Just something to look at.. this doesn't necessarily mean anything let us know what you see.... Mezz