Electrical gremlins

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Harry_p
Posts: 18
Joined: Thu Oct 22, 2020 10:34 pm

Electrical gremlins

Post by Harry_p »

Since buying my sud I’ve been chasing a problem which I’m not actually sure is a problem, or just a quirk.

The car hasn’t ever failed to turn over, hasn’t conked out when running, hasn’t actually broken down.

I have noticed that when driving at night with the lights on, interior fan on and wipers on, the battery light will glow slightly. It never comes fully on, but is bright enough that I can see it, and gets brighter and dims with each stroke on the wipers.

So far I have checked the alternator, fitted a new voltage regulator, built a hybrid alternator using the internals of a Mk2 golf 65a alternator with the front half of the sud one. Checked battery terminals, checked the main earth strap, cleaned up all the connectors to headlights, to the column stalks, to the dials, to the wiper motor etc.

I have fitted a relayed headlight supply to take load off the main power feed into the car, and replaced rear lights, sidelights and indicators with leds to further reduce electrical load. I have cleaned up the contacts in the column switches as well as you can without taking the whole thing to bits ( and probably breaking it )

Any other suggestions, or am I worrying for nothing? As I say, it’s not actually caused a problem as yet, I just don’t like seeing the feint glow of the battery light.
1969 fiat 850 saloon
1972 VW dormobile camper
1980 alfasud super 1.5
1987 VW golf gti
1989 BMW e30 M3
1990 Rover metro 1.1c
1994 Rover metro GTi 1.8
1996 BMW e36 M3 evo saloon
2001 BMW 320i touring
2006 Mercedes clk 350
2012 Alfa mito Multiair 135

Veesix75
Posts: 1549
Joined: Mon Jan 27, 2014 8:37 pm

Re: Electrical gremlins

Post by Veesix75 »

All my suds did that. I wouldn’t worry about it.

alfadave
Posts: 958
Joined: Sun Jan 17, 2016 6:57 pm

Re: Electrical gremlins

Post by alfadave »

Mine too!
If it bothers you, stick a bit of masking tape over it!

dave.armstrong
Posts: 220
Joined: Mon Feb 17, 2014 3:59 pm
Location: Stockport

Re: Electrical gremlins

Post by dave.armstrong »

The old car service managers saying when you take the car back "they all do that sir!" applies here. I've done everything on mine like you have including putting thicker cables to the alternator and battery. And guess what? The battery light still glows underload😭

Sud 145
Posts: 1354
Joined: Mon Jan 27, 2014 11:08 pm
Location: West Sussex.

Re: Electrical gremlins

Post by Sud 145 »

Not helpful I know but think I've only driven mine in the dark a handfull of times in 11 years.

User avatar
LooLooSud33Spider
Posts: 1093
Joined: Mon Dec 05, 2016 11:14 pm
Location: Staffordshire

Re: Electrical gremlins

Post by LooLooSud33Spider »

I can confirm this is not unusual .
1955 Austin A30 “S”
1973 Mg Midget
1983 1350 Sud Ti (soon to be 1500)
1996 33 1.7 16v racer
1997 916 spider 20v Turbo racer
2006 Porsche Cayman S
2006 Peugeot motorhome
2012 Skoda Octavia Vrs

alfadave
Posts: 958
Joined: Sun Jan 17, 2016 6:57 pm

Re: Electrical gremlins

Post by alfadave »

Like the guy who went to the Doctors.

" I can't stop singing old Tom Jones songs"

alfadave
Posts: 958
Joined: Sun Jan 17, 2016 6:57 pm

Re: Electrical gremlins

Post by alfadave »

My MoT guy told me a tail light was out.
Then said " you don't use it at night though do you"

Harry_p
Posts: 18
Joined: Thu Oct 22, 2020 10:34 pm

Re: Electrical gremlins

Post by Harry_p »

Thanks all, I’m quite happy to ignore it if it’s fairly normal.
1969 fiat 850 saloon
1972 VW dormobile camper
1980 alfasud super 1.5
1987 VW golf gti
1989 BMW e30 M3
1990 Rover metro 1.1c
1994 Rover metro GTi 1.8
1996 BMW e36 M3 evo saloon
2001 BMW 320i touring
2006 Mercedes clk 350
2012 Alfa mito Multiair 135

NEG
Posts: 268
Joined: Wed Oct 29, 2014 12:30 am

Re: Electrical gremlins

Post by NEG »

To join the chorus: mine does that as well....but not all the time! The warning bulb operates on a differential voltage, alternator output on one side and battery voltage on the other. When the engine is not running one side of the bulb is connected to 0v via the alternator/regulator with the other at 12v, so it lights up. With the engine running you have 12v either side of the bulb so it goes out....if there is some resistance in the wiring to the bulb on either side it will cause a voltage drop and thus a voltage differential and the bulb glows....

The wire from the alternator is also called the exciter and, as I understand it requires a small current draw to magnitise the field coil in the alternator so it can generate a voltage....

alfadave
Posts: 958
Joined: Sun Jan 17, 2016 6:57 pm

Re: Electrical gremlins

Post by alfadave »

My late Auto electrician told me that with the engine running, I should get approx 14.4V across the battery terminals.
Proves the alternator is doing its job.

User avatar
Mufasa
Posts: 165
Joined: Tue Jan 28, 2014 6:40 pm

Re: Electrical gremlins

Post by Mufasa »

Ditto as above but just to say nice fleet Harry
05Alfa1662.0GrigioGeo-Daily
03Alfa1561.8Sportwagon-BluCosmo
01Alfa1663.0Manual-Proteo Rosso
99Alfa1662.5V6GrigioNettuno-Track Car
84Alfasud1.5GoldCloverleafFlorentineCopper

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