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1st time ac problems

Help, Advice and DIY Tutorials on Volvo's extremely popular car line -- Volvo's 1990s "bread and butter" cars -- powered by the ubiquitous and durable Volvo inline 5-cylinder engine.

1992 - 1997 850, 850 R, 850 T5-R, 850 T5, 850 GLT
1997 - 2000 S70, S70 AWD
1997 - 2000 V70, V70 AWD
1997 - 2000 V70-XC
1997 - 2004 C70

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misha
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Year and Model: '97 850 2.5 20v
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misha

1st time ac problems

Post by misha » Thu Aug 29, 2019 2:03 am

Before i blame ecc control unit for failure i just need to know are ecc units interchangable for all 850s or there is a difference between years?
No flashing ac/rec lights but somehow i have a feeling that after around 30min air is not comming from the wents like it should.
Blower works on high speed and everything is fine for a while but after around 30min very little air comming out from the vents even if i hear that blower works at high speed.

Problem appeared after ac system is being checked and serviced.

When car sits overnight and everything is cooled down ac works perfectly...but after a while it starts to going on my nerves.

Never,ever had problems with ac since i have the car,except regular service around 3 years interval.
I suspect ecc or worn/slipping clutch on the compressor.


'97 850 2.5 20v /fully equipped/ Motronic 4.4 / polar white wagon
'91 Citroen XM 2.0 SI /fully equipped/mandarine red metallic
History of Volvos in the family:
'71 144 S
'73 144 De Luxe
'78 244 DL
'78 244 DL
'79 244 GLE
'85 340 GLS

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abscate
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Re: 1st time ac problems

Post by abscate » Thu Aug 29, 2019 3:57 am

If the air flow changes, Misha, something is up with the air dampers. It could be the ECC control unit but more likely a damper motor is not working right


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A Captain in a Sea of Estrogen
1999-V70-T5M56 2005-V70-M56 1999-S70 VW T4 BMW

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misha
Posts: 3939
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Re: 1st time ac problems

Post by misha » Thu Aug 29, 2019 7:20 am

Air dampers which lets air inside the cabin?
There are two of them right?
I think that they can't be both bad out of a sudden.
Also....all working fine for around 30min or so and ac blows ice cold...then something start acting up.
Something which controls them is making problem...in this case...it's ECC.
I suspect that it's rec motor.
I'll make flash code reader to see if ECC is complaining about something...but lights are not flashing.So i presume that there are no faults.
Is there a possibility that clutch is slipping when it becomes hot under the hood?


'97 850 2.5 20v /fully equipped/ Motronic 4.4 / polar white wagon
'91 Citroen XM 2.0 SI /fully equipped/mandarine red metallic
History of Volvos in the family:
'71 144 S
'73 144 De Luxe
'78 244 DL
'78 244 DL
'79 244 GLE
'85 340 GLS

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Clemens
Posts: 983
Joined: Thu Sep 03, 2015 12:34 pm
Year and Model: 96 855 R + 94 855 T5
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Clemens

Re: 1st time ac problems

Post by Clemens » Thu Aug 29, 2019 2:41 pm

as far as I know the ECC units are interchangeable regardless of the model year. at least in my case my 95 received a different year ECC and everything worked nicely again


Summer: 1996 855 R
Winter: 1994 855 T5M
Donor: 1995 854 10V

User avatar
misha
Posts: 3939
Joined: Sun Dec 07, 2008 4:09 pm
Year and Model: '97 850 2.5 20v
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misha

Re: 1st time ac problems

Post by misha » Thu Aug 29, 2019 2:49 pm

I thought about ECC units from up to '95 year cars because i can pull it out from '95.
If i could find one from '96 & '97 i know that they would work...no doubt about that.

What was the problem with yours ECC,Clemens?


'97 850 2.5 20v /fully equipped/ Motronic 4.4 / polar white wagon
'91 Citroen XM 2.0 SI /fully equipped/mandarine red metallic
History of Volvos in the family:
'71 144 S
'73 144 De Luxe
'78 244 DL
'78 244 DL
'79 244 GLE
'85 340 GLS

User avatar
abscate
MVS Moderator
Posts: 18194
Joined: Sun Feb 17, 2013 5:54 pm
Year and Model: 99T5 ,99S70,2005V70
Location: NYC, ALBANY NY
Has thanked: 200 times
Been thanked: 647 times
Trinidad & Tobago
abscate

Re: 1st time ac problems

Post by abscate » Fri Aug 30, 2019 3:24 am

The clutch slipping when hot is common, and is covered under the “ bread clip fix” here a lot. You can measure the clearance when cold to see if it’s in spec. I’ll look for threads with pictures


Empty Nester
A Captain in a Sea of Estrogen
1999-V70-T5M56 2005-V70-M56 1999-S70 VW T4 BMW

User avatar
misha
Posts: 3939
Joined: Sun Dec 07, 2008 4:09 pm
Year and Model: '97 850 2.5 20v
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misha

Re: 1st time ac problems

Post by misha » Fri Aug 30, 2019 12:31 pm

Is damper motor for air flaps accessible from under the steering wheel?
I would like to remove it and test it.
From what i read it is controled by ECC from various inputs from ac sensors.
I'm not removing the whole dash for this.


'97 850 2.5 20v /fully equipped/ Motronic 4.4 / polar white wagon
'91 Citroen XM 2.0 SI /fully equipped/mandarine red metallic
History of Volvos in the family:
'71 144 S
'73 144 De Luxe
'78 244 DL
'78 244 DL
'79 244 GLE
'85 340 GLS

User avatar
Clemens
Posts: 983
Joined: Thu Sep 03, 2015 12:34 pm
Year and Model: 96 855 R + 94 855 T5
Location: Austria
Has thanked: 67 times
Been thanked: 35 times
Austria
Clemens

Re: 1st time ac problems

Post by Clemens » Fri Aug 30, 2019 1:27 pm

misha wrote:
Thu Aug 29, 2019 2:49 pm

What was the problem with yours ECC,Clemens?
out of the blue, my fans would start ramping up and down, the temperature was very inconsistent and i had a bunch of codes that I can't remember.


Summer: 1996 855 R
Winter: 1994 855 T5M
Donor: 1995 854 10V

User avatar
misha
Posts: 3939
Joined: Sun Dec 07, 2008 4:09 pm
Year and Model: '97 850 2.5 20v
Location: Serbia
Has thanked: 30 times
Been thanked: 89 times
Serbia
misha

Re: 1st time ac problems

Post by misha » Fri Aug 30, 2019 3:45 pm

Strange that ac & rec lights are not flashing on start-up so i presume that there are no codes stored in ECC.
It starts acting up when things are warmed up.
When it sits overnight and everything is cooled down,it works normally.
I also figured out that it works perfectly in the night when there is no additional heat from direct sunlight.
Could be that solar sensor in front of windshield is at fault...or ECC is sending wrong information to damper motors.


'97 850 2.5 20v /fully equipped/ Motronic 4.4 / polar white wagon
'91 Citroen XM 2.0 SI /fully equipped/mandarine red metallic
History of Volvos in the family:
'71 144 S
'73 144 De Luxe
'78 244 DL
'78 244 DL
'79 244 GLE
'85 340 GLS

User avatar
abscate
MVS Moderator
Posts: 18194
Joined: Sun Feb 17, 2013 5:54 pm
Year and Model: 99T5 ,99S70,2005V70
Location: NYC, ALBANY NY
Has thanked: 200 times
Been thanked: 647 times
Trinidad & Tobago
abscate

Re: 1st time ac problems

Post by abscate » Fri Aug 30, 2019 6:34 pm

Clean the fan that pulls interior air in and feeds interior temp to the ECC control unit


Empty Nester
A Captain in a Sea of Estrogen
1999-V70-T5M56 2005-V70-M56 1999-S70 VW T4 BMW

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