90 300 tdi electrical fault

chrisstdt · Oct 2, 2021

Strange problem on my 90

Often when I brake or use the indicators the radio goes off (sat nav was playing up recently too but works fine in wife's car )

I thought a voltage spike due to a bad earth but multimeter in cig lighter reads around 14 volts with engine running and drops to about 13.6 when using anything electrical

Any suggestions?

Thanks

the_wolf · Oct 2, 2021

chrisstdt said:
Strange problem on my 90

Often when I brake or use the indicators the radio goes off (sat nav was playing up recently too but works fine in wife's car )

I thought a voltage spike due to a bad earth but multimeter in cig lighter reads around 14 volts with engine running and drops to about 13.6 when using anything electrical

Any suggestions?

Thanks

13.6 sounds pretty normal. Have you traced the stereo wiring back? The wiring is fairly simple so it may be chaffed somewhere as all you're likely to have is a switched live, a permanent live and an earth along with your speaker cables

payydg · Oct 2, 2021

That’ll be an earth issue

Disco1BFG · Oct 2, 2021

chrisstdt said:
multimeter in cig lighter reads around 14 volts

sadly, presence of good voltage, doesn't mean the circuit will carry current

.... it appears in your case, that this is the case

...

better to test circuits with an appropriate load - a headlamp bulb of about 55W ( and thus about 4.6A ) is a good test for most circuits - certainly anything fused at 10A had better be able to provide 5A without issue .... ( or else

)

Electrical maladies of this nature are always an earth issue.... broken wire / loose connection / verdigris ( AKA attach of the green crusties ) are all common ...

In your case, I'd be looking for a loose or corroded earth point - possibly on the BH ...

tottot · Oct 2, 2021

As above, the voltage reading say little. Dull slow indicators ?

mystery · Oct 2, 2021

chrisstdt · Oct 2, 2021

Thanks il check the wiring and earths

It's no standard as the radio and cigarette lighter are built into the cubby box

90 300 tdi electrical fault

chrisstdt

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the_wolf

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payydg

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Disco1BFG

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tottot

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mystery

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chrisstdt

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