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'95 850 ECC system stopped 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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Ozark Lee
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Re: '95 850 ECC system stopped working

Post by Ozark Lee »

BEJinFbk wrote:It seems odd that you would see all those failures at once.
I'm placing my bet on low voltage or a toasted ECC module.
I was thinking the same thing initially but the parasitic draw is key off. The controller should be out of the picture at that point. This one will be fun to see how it gets resolved.

...Lee
'94 850 N/A 5 speed
'96 Platinum Edition Turbo
Previous:
1999 V70XC - Nautic Blue - Totaled while parked.
1999 V70XC - RIP - Wrecked Parts Car.
1998 S70 T5
1996 850 N/A
1989 740 GLT
1986 740 GLT
1972 142 Grand Luxe

DiggerDaz
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Year and Model: 1998 C79
Location: Auckland
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Post by DiggerDaz »

Read on for a solution. Mines a 1994 but it seems the same sort of thing as discussed on this thread.

I've had the flashing LEDs for around 3 years. The aircon doesn't work due to loss of gas but as long as it blows ambient or warm/hot air I'm happy. Then it stopped blowing.

I went to the blower motor and it's was pretty clean and free to spin but I took it apart and gave it a good clean of the carbon residue and lubed the bearings. Which didn't fix it. I then bridged the 'resistor'/power module and the motor ran. So then into the 'resistor'. The FET measured fine so I replaced all of the electrolytic capacitors and resoldered some dry joints. I removed D4 (discussed elsewhere) because it looked crusty and I couldn't measure a silicon junction across it. I was greeted with the capacitor 'cat pee' smell. Cleaning up the board, refitted D4 and suddenly I could measure a junction again!

At this point it was time to test so back into the car and bingo! Working.

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