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1997 volvo 850 ecc a/c control unit not working

Help, Advice and DIY Tutorials on Volvo's P80 platform cars -- Volvo's 1990s "bread and butter" cars -- powered by the ubiquitous and durable Volvo inline 5-cylinder engine.

1992 - 1997 850, including 850 R, 850 T-5R, 850 T-5, 850 GLT
1997 - 2000 S70, S70 AWD
1997 - 2000 V70, V70 AWD
1997 - 2000 V70-XC
1997 - 2004 C70

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nesman321
Posts: 6
Joined: 29 March 2016
Year and Model: 1997 850 t5
Location: cary

1997 volvo 850 ecc a/c control unit not working

Post by nesman321 »

I was wondering if you guys could help me try to figure out what going wrong with my car. So I was trying to fix the defroster on my car i took the motors out for the flaps for the ac and I took them apart and re-lubed them. And unstuck the flaps and put all the motors back into the car except for the one by the foot on the drive side and took a drive around town it worked great so the next day. I put the last motor back in and now my ac controller won't work the flap motor isn't responding the blower fan won't blow and there is no light on the ecc controller I check to make sure there is still power going to the cable to the ecc controller and I still get a 12-volt power and i took it apart to see if they're like a bad solder joint or something and I can't see anything bad inside the controller. I dont know what else to check unless the ecc controller died and since my car is 1997 i still need to build the led code reader that goes into the obd2 port to see if that shows anything but idk what else to do so thanks for the help.

nesman321
Posts: 6
Joined: 29 March 2016
Year and Model: 1997 850 t5
Location: cary

Post by nesman321 »

built the code reader it just stays solid red. and won't respond to the button. and I was able to power the ecc controller outside of the car with a benchtop power supply and it had its lights on. so I'm guessing something in the car that is causing a short.

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Roger_850T
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Post by Roger_850T »

For a 1997 car, I am told that OBD-II works. (I have a 1995, and have to use the LED blink code under the hood.) If you have a reader available, you might give it a try.

Roger
11 XC60 137k
08 V50 Project... Still in pieces
05 XC90 V8 213k
95 854T 350k Still my favorite daily driver
02 V70 186k+ Gave to my daughter, still going strong
03 S80 111k (crashed, but driver walked away unhurt)
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nesman321
Posts: 6
Joined: 29 March 2016
Year and Model: 1997 850 t5
Location: cary

Post by nesman321 »

ya, my code read works when I use it on another pin like the one for the ecu on the obd2 port, and if tried a reader with no luck. I know there is something wrong with the wiring going to the ecc controller cause I can power it outside of the car with a benchtop power supply and it turns on the lights for the ac and rec lights. But it won't in the car and when the plug is in that gives it the power to the ecc controller it makes my tester led stay solid red and my ecc controller won't turn on no light on the ac or rec light.so I think there is a short with the wiring going to the ecc controller.

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misha
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Year and Model: '97 850 2.5 20v
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Post by misha »

Roger_850T wrote: 27 Nov 2023, 15:26 For a 1997 car, I am told that OBD-II works. (I have a 1995, and have to use the LED blink code under the hood.) If you have a reader available, you might give it a try.

Roger
'97 850 ECC still produce flash codes and readout is done via OBDII port with a blink code reader.
Fully OBD II compliant ECC begins with s,v70.
'97 850 2.5 20v / fully equipped / Motronic 4.4 from the factory / upgraded with S,V,C,XC70 instrument cluster / polar white wagon
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

xHeart
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Post by xHeart »

misha wrote: 27 Nov 2023, 18:11
Roger_850T wrote: 27 Nov 2023, 15:26 For a 1997 car, I am told that OBD-II works. (I have a 1995, and have to use the LED blink code under the hood.) If you have a reader available, you might give it a try.

Roger
'97 850 ECC still produce flash codes and readout is done via OBDII port with a blink code reader.
Fully OBD II compliant ECC begins with s,v70.
+1

VIDA/DiCE can be hooked up for limited diagnostic, however it gives you all repairs and procedure to fix.

I miss mine, here is my history of 1997 Volvo 850 search.php?keywords=1997+Volvo+850&term ... mit=Search

Maintenance Log with references viewtopic.php?f=35&t=46831
--
Golden-German Shepherd | 2021 XC90 T6 INSCRIPTION (Nexa) | 2020 V60CC (Frska) | 2013A XC90 (Lktra)
Past: Golden Retriever | 2001 V70XC | 1997 Volvo 854 | 1989 Volvo 740 GL | 1979 Volvo 240

xHeart
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Post by xHeart »

nesman321 wrote: 15 Nov 2023, 07:59 I was wondering if you guys could help me try to figure out what going wrong with my car.
This was our 1997 850. I've many usable new and used parts; NOT junk. I'm happy to box and ship it to you for $1!

Image
--
Golden-German Shepherd | 2021 XC90 T6 INSCRIPTION (Nexa) | 2020 V60CC (Frska) | 2013A XC90 (Lktra)
Past: Golden Retriever | 2001 V70XC | 1997 Volvo 854 | 1989 Volvo 740 GL | 1979 Volvo 240

nesman321
Posts: 6
Joined: 29 March 2016
Year and Model: 1997 850 t5
Location: cary

Post by nesman321 »

xHeart wrote: 01 Dec 2023, 10:34
nesman321 wrote: 15 Nov 2023, 07:59 I was wondering if you guys could help me try to figure out what going wrong with my car.
This was our 1997 850. I've many usable new and used parts; NOT junk. I'm happy to box and ship it to you for $1!

Image
you would do that I would be grateful and that a nice looking 850 looks like mine but in a nicer condition

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V50M66
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Post by V50M66 »

VIDA/DiCE won’t tell you much of anything on pre-‘99 cars. For ‘96-‘98 the 850 OBDII app is your best option for fantastic affordable diagnostics
1998 V70 AWD - Emerald Green/Tan - M56/Delta link swap, VAST tuned, lots of fun
1998 V70 NA - Nautic Blue/Charcoal - Factory M56/slicktop track car
2006 XC70 Ocean Race - workhorse
2002 S40 1.9T - daily

2004 XC70 - Mystic Silver/Black - former workhorse, parted
2005 V50 T5 M66 FWD - Black Stone/Black leather - former garage queen, sold

xHeart
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Post by xHeart »

nesman321 wrote: 03 Dec 2023, 11:55 you would do that I would be grateful...
... we're grateful to MVS.
I'll pull it together and ship it to you after the holiday traffic -- includes repair manual and tools intended for our 1997 850.
Please PM me your shipping address when convenient, nesman321!

Happy Holidays!
--
Golden-German Shepherd | 2021 XC90 T6 INSCRIPTION (Nexa) | 2020 V60CC (Frska) | 2013A XC90 (Lktra)
Past: Golden Retriever | 2001 V70XC | 1997 Volvo 854 | 1989 Volvo 740 GL | 1979 Volvo 240

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