Heated rear window fault

Body parts, seats, dash, headlining, windows and stuff!

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Zag
Regular Poster
Posts: 120
Joined: Mon Aug 28, 2017 04:35
Model: Excel SE
Colour: Ice Blue
Year: 1986
Location: East Yorkshire

Re: Heated rear window fault

Post by Zag »

Zaphod wrote:
Tue Dec 10, 2024 15:43
Zag wrote:
Sun Dec 08, 2024 10:47
Section md sheet 30 shows its location to be next to the fuel tank on the near side. Its description is low kevel tell tale relay, further reinforcing that it has nothing to do with the gauge.
My car is a post 89 car, and is the next section of electrical diagrams
Section mh in sheet 5 shows the circuit, mh page 9 shows it under steering column, code g last one before the fuses.

Zag
Regular Poster
Posts: 120
Joined: Mon Aug 28, 2017 04:35
Model: Excel SE
Colour: Ice Blue
Year: 1986
Location: East Yorkshire

Re: Heated rear window fault

Post by Zag »

But still only does the light not the gauge.

Zaphod
Senior Poster
Posts: 284
Joined: Mon Aug 23, 2021 21:38
Model: Excel SE
Colour: Blue
Year: 1990
Location: Uffington

Re: Heated rear window fault

Post by Zaphod »

That's the one I have out, it claims to be a low fuel level relay but having had a look inside it its clear it does a bit more than that. It has a 555 timer IC which is probably used to illuminate the low fuel light. However there are too many components on the PCB for that to be all its doing (I am very familiar with the 555 timer IC), it could well also be smoothing any waves in the signal to the gauge. There is one electrolytic cap in there and those are known for failing with age, along with a few other age sensitive components.
Of all the things I have lost I think I miss my mind the most...

1952 MG TD
1957 MGA 1500
1959 Austin Healey Sprite
1975 MG Midget 1500
1990 Lotus Excel

Zaphod
Senior Poster
Posts: 284
Joined: Mon Aug 23, 2021 21:38
Model: Excel SE
Colour: Blue
Year: 1990
Location: Uffington

Re: Heated rear window fault

Post by Zaphod »

Just found this, and if it works as I suspect, as a smoothing circuit it may do the job..
https://www.ebay.co.uk/itm/375064897187 ... R96Yzd2DZQ
Of all the things I have lost I think I miss my mind the most...

1952 MG TD
1957 MGA 1500
1959 Austin Healey Sprite
1975 MG Midget 1500
1990 Lotus Excel

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