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850 dash warning lights Topic is solved

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

crlande
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crlande

Re: 850 dash warning lights

Post by crlande » Thu Jan 30, 2020 3:00 pm

Thank you. Thinking about tossing a regulator at it since that seems easier than yanking the alternator.

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misha
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misha

Re: 850 dash warning lights

Post by misha » Thu Jan 30, 2020 3:58 pm

If diodes are shot....the easiest solution would be a replacement(used) alternator.

BUT...usually....when diode(s) are shot,the battery warning light is always ON...even when the key is removed from ignition.

Do you have a battery warning light ON along with all other lights when key is in pos.II(bulb check),before starting the car?
Last edited by misha on Thu Jan 30, 2020 4:58 pm, edited 1 time in total.
'97 850 2.5 20v / fully equipped / Motronic 4.4 from the factory / upgraded with S,V,C,XC70 instrument cluster / 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

crlande
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Joined: Sat Jul 27, 2013 8:48 pm
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crlande

Re: 850 dash warning lights

Post by crlande » Thu Jan 30, 2020 4:38 pm

It looks more like the reflection from the bright adjacent warning light is lighting the battery warning light. But the battery light looks very dim compared to the one next to it. Where are you leading me with this idea?

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misha
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Re: 850 dash warning lights

Post by misha » Thu Jan 30, 2020 4:50 pm

If the battery warning light is burnt,open circuit,shorted to ground,or the thin wire which goes to the alternator above b+ terminal is disconnected or shorted... the alternator will NOT have the output.

That thin wire is signal for battery light on the dash and it also have "awakening" role for the alternator.
'97 850 2.5 20v / fully equipped / Motronic 4.4 from the factory / upgraded with S,V,C,XC70 instrument cluster / 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

crlande
Posts: 287
Joined: Sat Jul 27, 2013 8:48 pm
Year and Model: 240DL;850;S70
Location: Lehigh Valley, PA
Has thanked: 1 time
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crlande

Re: 850 dash warning lights

Post by crlande » Thu Jan 30, 2020 5:00 pm

So I could now be hunting for an issue with the thin wire? I am not good at tracing electrical shorts, this is getting deeper down the hole!

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misha
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Re: 850 dash warning lights

Post by misha » Thu Jan 30, 2020 5:08 pm

It's just the possibillity.
If the bulb is ok and signal wire(thin wire) is ok...than alternator(regulator)is bad.

It's easier to remove the cluster to check the bulb than to remove the alternator.

On that thin wire...you should have a battery voltage present with key in pos.II.
If you have voltage on it and bulb is ok....again...the alt. is bad.
'97 850 2.5 20v / fully equipped / Motronic 4.4 from the factory / upgraded with S,V,C,XC70 instrument cluster / 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

crlande
Posts: 287
Joined: Sat Jul 27, 2013 8:48 pm
Year and Model: 240DL;850;S70
Location: Lehigh Valley, PA
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crlande

Re: 850 dash warning lights

Post by crlande » Thu Jan 30, 2020 5:41 pm

This sounds like a doable plan to check this further.

Chuck W
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Re: 850 dash warning lights

Post by Chuck W » Thu Jan 30, 2020 9:33 pm

Now that you say that you don't have a Battery light on with key on, I just went through a similar issue on my '97 T5.

You probably also have a couple more lights that aren't coming on. From my post on it.
I had gotten some weird dash lights on Wed (Low Fuel and SRS lights would flash on the interstate, and eventually came on when I got off the highway). When I got home I checked and I had no Battery light on key "ON". (Actually, no Battery, Parking Brake, Brake Warning, Bulb Failure lights). Taking the D+ wire (The small wire) to ground gave me all the appropriate lights, to the bulb was good, so the problem was in the alternator or regulator, and the odd lights were due to low battery voltage.
I was going to swap the regulator, but the bearings sounded like so much gravel in the alternator, I just pulled another spare I had in the garage and installed it. After that, the car has run fine, and all of the lights work and it charges are as it should.

Upon inspecting the original alternator, the brushes on the regulator had worn down to where they were no longer, or barely, touching the slip ring. I never saw a low battery light "glow", so I think the regulator just gave it up.

You can replace the regulator while the alternator is in the car, but it's kind of a pain. Even more of a pain perhaps than just pulling the alternator.

crlande
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crlande

Re: 850 dash warning lights

Post by crlande » Sat Feb 01, 2020 1:13 pm

Yes you may be correct. I hear a grinding, growling noise somewhere near the serpentine belt for a short time at start up.

crlande
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crlande

Re: 850 dash warning lights

Post by crlande » Tue Feb 04, 2020 1:12 pm

Hey misha! I measured 7.5 volts on the thin wire with key pos II. Not sure if that means anything. FCEuro alternator is being shipped here.
Thanks again.
Carl

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