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1996 850 Wagon Service Light On 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

PeteB
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PeteB

Re: 1996 850 Wagon Service Light On

Post by PeteB » Thu Oct 10, 2019 9:08 am

Obviously an amp-clamp is the way to measure the wires individually, wonder if the
parts stores have them to loan.



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PeteB

Re: 1996 850 Wagon Service Light On

Post by PeteB » Fri Oct 11, 2019 5:16 pm

I probably should have started a new thread about the battery dying overnight.

After sleeping on it, I'm guessing that an always hot wire is pinched before the
fuse since pulling fuses didn't cure the high draw. Perhaps it has something to
do with the smashed door - we should replace it ASAP.



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abscate
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abscate

Re: 1996 850 Wagon Service Light On

Post by abscate » Sat Oct 12, 2019 5:45 am

Quick check, undo door harness and see if draw drops
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PeteB


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PeteB

Re: 1996 850 Wagon Service Light On

Post by PeteB » Mon Oct 14, 2019 5:47 am

It would be great to have a wiring harness that highlights all the always on wiring for just
this sort of problem.



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PeteB

Re: 1996 850 Wagon Service Light On

Post by PeteB » Wed Oct 30, 2019 8:38 pm

OK, got an amp clamp on sale from Sears and checked it out today.
The large bundle of smaller wires at the positive batter post does have one yellow
wire, I previously thought they were all red. The yellow wire has the high draw.
Anyone know what this wire is?
I might just snip it and see what is not working in the car, then solder it back.

I went through all the pages in the wiring diagrams that I could find and did not
find any yellow wire coming off the battery positive. I think that the diagram was
from 1995, not sure.

I had one more thought to pull the engine ECU or any module that plugs in before I
cut the wire.
Last edited by PeteB on Sat Nov 02, 2019 7:34 am, edited 2 times in total.



PeteB
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PeteB

Re: 1996 850 Wagon Service Light On

Post by PeteB » Wed Oct 30, 2019 8:46 pm

I googled "yellow wire at battery post Volvo 850" and found this thread with another
person having the same problem. They snipped the wire and the car works fine, LOL!
But I'm sure that something is not going to work:
https://volvoforums.com/forum/volvo-850 ... nal-84878/

This is their picture but here is the yellow wire:
VOLVO-850-YELLOW-WIRE.jpg
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abscate
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abscate

Re: 1996 850 Wagon Service Light On

Post by abscate » Wed Oct 30, 2019 10:09 pm

That’s aftermarket stuff. Wiring diagrams aren’t going to help there


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Re: 1996 850 Wagon Service Light On

Post by PeteB » Thu Oct 31, 2019 7:53 am

I don't think so, all those reds and the yellow normally go into a big lug that certainly
looks to be factory. In that picture the guy cut out the big factory lug in order to find
the leakage current, then put new lugs on the wires.
That car and our car both have the yellow wire that goes into the factory harness so
I'm quite sure that it is factory.



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Re: 1996 850 Wagon Service Light On

Post by ZionXIX » Thu Oct 31, 2019 9:53 am

Assuming you have time, you could follow it and solve the mystery!



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Re: 1996 850 Wagon Service Light On

Post by PeteB » Fri Nov 01, 2019 3:22 am

I'm able to follow it about one foot then it enters a large harness.



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