Electrical Faults of my car - How are they related if at all?

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MisterH
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Electrical Faults of my car - How are they related if at all?

Post by MisterH » Sat Jan 26, 2019 5:11 pm

when working on the car today, it has become clear to me that these are the most pressing of the car's electrical faults:

Left hand Popup does not pop up (didn't get around to having a look, was trying to sort other issues)

the horn is seemingly disconnected, but still makes a relay click

the brake lights do not work, even though all the other rear lights work

the Speedometer is not working, although I haven't been able to lay eyes on the sensor yet, the Haynes manual tells me where it should be

Are these issues all related (other than the fact they are electrical)?
also, there are 2 mystery fuses in the storage compartments in the centre console
Image
does anyone know what this is needed for?
Many thanks
Current Jobs to do (30/12/19):
New Tires
Fix Radio/Cassette
Fix Central Locking
Bodywork

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brinkie
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Re: Electrical Faults of my car - How are they related if at all?

Post by brinkie » Sat Jan 26, 2019 6:21 pm

Short answer: NONE are related. Long answer will follow when I have finished my long list of people asking for advice how to fix pressing electrical faults to their car. :lol:
Robert.

Present cars: 1994 Volvo 480 GT 2.0i Vase Green, 2010 Volvo V70 2.0F Momentum Mystic Silver
Past: 1981 Talbot-Matra Murena 2.2 Rouge Mephisto, 1995 Volvo 480 GT 2.0i Paris Blue

jifflemon
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Re: Electrical Faults of my car - How are they related if at all?

Post by jifflemon » Sat Jan 26, 2019 7:02 pm

Re: the mystery fuses. Check your fuse box (drivers side dashboard). It should be labeled with the correct fuses (they vary between models and years) however they could simply be that previous owner needed 1 fuse and they came in a pack of 3!

arthuy
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Re: Electrical Faults of my car - How are they related if at all?

Post by arthuy » Sat Jan 26, 2019 7:06 pm

check that you have continuity with the speed cable, it is notorious for breaking. Mine had in multiple places in the engine bay and I had to replace the whole length.

Pop up could be the motor, bulbs (does your running lights work?) Good thing is you can put them up by rotating the wheel on the motor.

With Volvo 480 electrics you need to digest the wiring diagrams and work through methodically.

dcwalker
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Re: Electrical Faults of my car - How are they related if at all?

Post by dcwalker » Sat Jan 26, 2019 7:35 pm

As has been said they are not related, I'm afraid - that would be too easy an answer for a 480! :rofl:

Your problems in the order you raise them:

LH pop-up - this could be a problem with the relay (tall double one in the relay box), the motor itself (which can be overridden by turning the knurled knob on the rear) or a DRL bulb. Is it the correct (and working) 21/4W bulb in the DRL? Are the connections corroded?

Horn - most likely the horns themselves are kaput. Not uncommon for both to go on cars (spent ages chasing this problem on an S40 because I couldn't believe both had died, but when you think about it they are the same age). Also worth checking the connections aren't too badly corroded (especially if you are missing the engine undertray).

Brake-lights - could be a faulty switch at the pedal (or for some reason has gone out of adjustment? I am assuming you have checked all fuses...

Speedo - as has been said here and elsewhere, it's actually quite rare for the speedo sensor itself to pack up. Usually it's the wiring breaking up - it's a shielded cable with a connector under the air filter housing. Often worth cutting the connector out and joining the wires directly. Also check the connectors at the back of the instrument panel - are they firm? Might also be a solder issue on the PCB - for which a holiday with Brinkie is usually the answer.

Hope some of that helps!

David
Current: 1994 480 GT, 1995 480 Celebration 467/480 (plus 2004 C70 Collection)
Previous: Celebration 346 (sold to Alan480), Celebration 269 (scrapped abandoned project), Celebration 73, 1992 ES, 1988 ES - and numerous other non-480 Volvos!

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MisterH
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Re: Electrical Faults of my car - How are they related if at all?

Post by MisterH » Sat Jan 26, 2019 7:41 pm

Thank you everyone for your help, next time I work on the car I will have a look at those. I aim to have the car MOT-ready by next weekend, I will let you know how I get on
Current Jobs to do (30/12/19):
New Tires
Fix Radio/Cassette
Fix Central Locking
Bodywork

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