S3 Electrical Problem

Technical advice Q&A

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Neil Duke
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#1 S3 Electrical Problem

Post by Neil Duke » Fri Jan 24, 2020 9:03 am

Hi,I have just bought an S3.It was rebuilt some years ago,& has stood for years.The lights,indicators,& brake lights don't work,but the hazzard warning lights do.Fuel gauge not giving a reading.I am sure there will be many more questions,as I have collected it,& driven it home,using good,old fashioned ,hand signals.
S3 Roadster Manual
07 Vanquish S
07 Vantage Roadster
74 Triumph Stag
66 Scimitar Coupe
He who dies with the most toys wins.

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mgcjag
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#2 Re: S3 Electrical Problem

Post by mgcjag » Fri Jan 24, 2020 9:57 am

Check all the fuses....clean up the fuse holders they often cause problems....do you have a wireing diagram..see knowledge base section if not....Steve
Steve
1969 S2 2+2 & Building a C type replica

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Neil Duke
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#3 Re: S3 Electrical Problem

Post by Neil Duke » Fri Jan 24, 2020 10:58 am

I have got a wiring diagram.I will be checking connections,& fuses at the weekend.Just wondered if this was a regular problem.Thank you.
S3 Roadster Manual
07 Vanquish S
07 Vantage Roadster
74 Triumph Stag
66 Scimitar Coupe
He who dies with the most toys wins.

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abowie
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#4 Re: S3 Electrical Problem

Post by abowie » Fri Jan 24, 2020 11:44 pm

A car sitting for 5 years might well develop gremlins; Lucas was the Prince of Darkness, after all.

I'll preface this by saying that I'm not very experienced with S3 cars.

The fuses are found behind the central drop down instrument panel. They are numbered 1 to 8, starting top left downwards for 1 - 4, then 5 -8 are top to bottom right.

Headlights/high beam are fuse 1 and 2 respectively.

Indicators and brake lights from fuse 6.

The fuel gauge power comes from fuse 7 via a 12/10v voltage regulator mounted on the centre drop down panel.

So if it's fuses, at least half of them don't work. Which is a bit odd.

Other things to consider.

Fuel gauge. First check to see if the water temp gauge is working. It gets 10v power from the same voltage regulator and if it works, your problem is not the 10v supply to the fuel gauge. Then check that the fuel sender unit actually works; it's in the top of the tank under the boot boards. It should change resistance when the float is moved up or down.

The lights and indicators all go through the indicator switch, so many of your problems may actually be with it.

I've also sent you a private message.
Last edited by abowie on Fri Jan 24, 2020 11:49 pm, edited 1 time in total.
Andrew.
881824, 1E21538. 889457..oops. Jezza the V12 XJS race car.
http://www.projectetype.com/index.php/the-blog.html
Adelaide, Australia

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#5 Re: S3 Electrical Problem

Post by abowie » Fri Jan 24, 2020 11:46 pm

Image
Andrew.
881824, 1E21538. 889457..oops. Jezza the V12 XJS race car.
http://www.projectetype.com/index.php/the-blog.html
Adelaide, Australia

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Neil Duke
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#6 Re: S3 Electrical Problem

Post by Neil Duke » Sat Jan 25, 2020 6:38 am

Having a quick look last night,I found this in-line fuse holder to have the wrong type of fuse in it.Can you tell me what this one is for?& what size fuse it should be?Thanks for your help.Image
Image
S3 Roadster Manual
07 Vanquish S
07 Vantage Roadster
74 Triumph Stag
66 Scimitar Coupe
He who dies with the most toys wins.

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Neil Duke
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#7 Re: S3 Electrical Problem

Post by Neil Duke » Sat Jan 25, 2020 6:49 am

The lights and indicators all go through the indicator switch, so many of your problems may actually be with it

This sounds promising
S3 Roadster Manual
07 Vanquish S
07 Vantage Roadster
74 Triumph Stag
66 Scimitar Coupe
He who dies with the most toys wins.

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driver
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#8 Re: S3 Electrical Problem

Post by driver » Sat Jan 25, 2020 7:02 am

Hi Rob Gill here,
might be worth checking/cleaning as many earth connections as possible.
All the best.

(ref other subjects you cant beat a good s3 ! :bigrin: )
v12 etype 2+2

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abowie
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#9 Re: S3 Electrical Problem

Post by abowie » Sat Jan 25, 2020 8:32 am

Neil Duke wrote:
Sat Jan 25, 2020 6:38 am
what size fuse it should be
Again, not a S3 expert but looks aftermarket...
Andrew.
881824, 1E21538. 889457..oops. Jezza the V12 XJS race car.
http://www.projectetype.com/index.php/the-blog.html
Adelaide, Australia

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vee12eman
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#10 Re: S3 Electrical Problem

Post by vee12eman » Sat Jan 25, 2020 8:51 am

Hi.

Should be a 35A glass fuse. Note the rate of glass fuses is different from the actual rate, but they are normally described by the blow rating, from memory, 35A fuses have a 17A continuous rating.
It’s not an after market fuse, correct for S3.

Regards,

Simon.
Image

Edit:

Here’s the correct fuse:


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Simon S-Y
Series III FHC

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mgcjag
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#11 Re: S3 Electrical Problem

Post by mgcjag » Sat Jan 25, 2020 9:26 am

The inline fuse with 2 brown wires is for the horn....there is another fuse that powers sidelamps, brake lamps, numberplate lamp, all of the panal lamps fead from the Red Black of the headlamp switch .......The service manual and wireing diagrams should be your best friends now you have a S3...they will be invaluable.....Steve
Steve
1969 S2 2+2 & Building a C type replica

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Neil Duke
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#12 Re: S3 Electrical Problem

Post by Neil Duke » Sat Jan 25, 2020 9:34 am

Thanks guys,I will take another look,when I get back from work.
S3 Roadster Manual
07 Vanquish S
07 Vantage Roadster
74 Triumph Stag
66 Scimitar Coupe
He who dies with the most toys wins.

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davef
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#13 Re: S3 Electrical Problem

Post by davef » Sat Jan 25, 2020 9:02 pm

I believe that the fuse on the frames also powers the fans. I had that blow on a trip to France when one of the Fans let go, took 20 mins in the queue for the tunnel to find the problem, minutes to fix, lucky I had a spare.

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