940 air con

sebsvolvo · Nov 6th, 2015, 07:52

Hi , I have a problem with the heating system, the air con compressor seems to work intermitently when we switch the blower on to demist the screen. According to the dashboard switch the air con should be off,and the heating dial is on 24. Is this normal?
Thanks Seb

schicksal · Nov 6th, 2015, 12:33

If your compressor is cycling off and on while it should be engaged your system is probably low on refrigerant due to a leak somewhere.

760Simon · Nov 6th, 2015, 12:40

Hi, I pretty sure the AC is supposed to come on when you switch it to de-missed well it does on my 760 as the cooling action take the moisture out of the air even though you will have the heat on, I could be wrong that's the norm but there should be someone on here that will put you right

CTCNetwork · Nov 6th, 2015, 13:00

Hi,

The default action for cars fitted with AirCon and when demist option is selected is for the AirCon to be working. You will see the AirCon light on the switch on when clearing the front screen.

You would be best to check the compressor and see what is happening.
As mentioned if the system is low on gas then the clutch will kick in and out more and more rapidly to the point where the system will stop trying. So if the wheel is stationary even with the belt then you're all out of gas.

If you use AirCon infrequently it is probably the seals gone/going. But get the system tanked up with refrigerant and whatever uv leak detector they use to see where you are losing your gas.
You also need to use the system regularly - at least one a week to help keep the system in good leak free condition.

Des. . .

sebsvolvo · Nov 6th, 2015, 17:24

Thanks for all the help,I will get the system topped up and see what happens
and report back
Seb http://www.volvoforums.org.uk/images.../thumbs_up.gif

Rversteeg · Nov 9th, 2015, 12:11

If a low refrigerant level is low the low pressure switch causes the system to cycle on/off very frequently. You can test by temporarily bypassing this switch. Take the connector from the switch (located on the aluminium can shaped part on the exhaust side of the engine) and connect both reminal of the connector with eg a paperclip. If the cycling is now back to a normal frequency your refrigerant level is too low.
Note bypassing the switch is not a permanent solution and as long as you do not have the system refilled you should not use it. You can disable the AC system by taking out the paperclip and leaving the connector loose from the switch.

sebsvolvo · Nov 10th, 2015, 20:27

Thanks for the explanation,I will test to see if I am low on gas.Good to know I can bypass the ac system and still use the heating system
Seb

Nov 6th, 2015, 07:52	#1
sebsvolvo New Member Last Online: Feb 4th, 2018 13:27 Join Date: Apr 2015 Location: falaise	940 air con Hi , I have a problem with the heating system, the air con compressor seems to work intermitently when we switch the blower on to demist the screen. According to the dashboard switch the air con should be off,and the heating dial is on 24. Is this normal? Thanks Seb

Nov 6th, 2015, 13:00	#4
CTCNetwork Forum Support Team Join Date: Dec 2004 Location: Liège, Belgium View Photos By: CTCNetwork	Hi, The default action for cars fitted with AirCon and when demist option is selected is for the AirCon to be working. You will see the AirCon light on the switch on when clearing the front screen. You would be best to check the compressor and see what is happening. As mentioned if the system is low on gas then the clutch will kick in and out more and more rapidly to the point where the system will stop trying. So if the wheel is stationary even with the belt then you're all out of gas. If you use AirCon infrequently it is probably the seals gone/going. But get the system tanked up with refrigerant and whatever uv leak detector they use to see where you are losing your gas. You also need to use the system regularly - at least one a week to help keep the system in good leak free condition. Des. . . __________________ Density:- Not just a measurement ~ It's a whole way of Life.! ! ! I drive a Volvo, Please Don't Get In My Way! OldVolvos4Ever He shows up. People die. He vanishes. People should not be afraid of their governments. "He'll deliver more justice in a weekend than 10 years of your Governments should be afraid of their people... "V" courts & tribunals. Just stay out of his way." "I plan to." Last edited by CTCNetwork; Nov 6th, 2015 at 13:05.

Nov 9th, 2015, 12:11	#6
Rversteeg Master Member Last Online: Today 15:32 Join Date: Feb 2006 Location: Amersfoort (NL)	Testing If a low refrigerant level is low the low pressure switch causes the system to cycle on/off very frequently. You can test by temporarily bypassing this switch. Take the connector from the switch (located on the aluminium can shaped part on the exhaust side of the engine) and connect both reminal of the connector with eg a paperclip. If the cycling is now back to a normal frequency your refrigerant level is too low. Note bypassing the switch is not a permanent solution and as long as you do not have the system refilled you should not use it. You can disable the AC system by taking out the paperclip and leaving the connector loose from the switch.

Nov 6th, 2015, 12:33	#2
schicksal Member Last Online: Jun 11th, 2019 13:41 Join Date: Oct 2015 Location: Charleston	If your compressor is cycling off and on while it should be engaged your system is probably low on refrigerant due to a leak somewhere.

Nov 6th, 2015, 12:40	#3
760Simon Getting old disgracefully Last Online: Apr 20th, 2024 17:14 Join Date: Jan 2009 Location: South Essex	Hi, I pretty sure the AC is supposed to come on when you switch it to de-missed well it does on my 760 as the cooling action take the moisture out of the air even though you will have the heat on, I could be wrong that's the norm but there should be someone on here that will put you right

Nov 6th, 2015, 17:24	#5
sebsvolvo New Member Last Online: Feb 4th, 2018 13:27 Join Date: Apr 2015 Location: falaise	Thanks for all the help,I will get the system topped up and see what happens and report back Seb http://www.volvoforums.org.uk/images.../thumbs_up.gif

Nov 10th, 2015, 20:27	#7
sebsvolvo New Member Last Online: Feb 4th, 2018 13:27 Join Date: Apr 2015 Location: falaise	Thanks for the explanation,I will test to see if I am low on gas.Good to know I can bypass the ac system and still use the heating system Seb

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