S130 warning light development

[checkrail]

Continuing the saga, with the master switch on, the warning light is on, turn ignition on warning light goes off. If I remove the interior light fuse the light goes out so it must be getting power from one of the many lights on that circuit

[JonB]

Why start a new topic? It’s normal to post updates on the original topic.

[Craven]

Interior lights is one of the circuit that is permanently live regardless of ignition switch.
Very likely your feed is from one of these permanent on circuit, What effect does the hand brake on/off have.

[checkrail]

The handbrake light works through the ignition circuit, the one causing the trouble is not on when the ignition is.
At the moment all the door lights, bonnet and boot lights work but the brake one stays on.

[Craven]

Love these S130 diagrams the circuit I have shows Hand Brake and fluid warning lamp as the same lamp, I understand the conditions you are describing, you have I believe is one where the warning lamp through a short circuit is has picked up the interior light circuit supply +12v the earth side circuit is being found via a device that is only powered when the ignition is turned on the warning lamp will then have +12v on both sides and go out.

[checkrail]

I think possibly the later +2's had the same warning lamp. At one point today the lamp dropped down in brightness for a few seconds and then returned
The original warning light terminal no longer is showing live.

[checkrail]

Things have gone from bad to worse, checking wires under the dash i've managed to upset them in the tacho area.. I 've lost the ignition light/feed.
Can somebody tell me what to look for amongst the jumble, I've removed the voltage stabiliser to give a bit more room.

Thanks very much John

[billwill]

Thia is the basic circuit of the old style tachometer:




This is the basic ignition circuit of a car with ballast-resistor ignition.



With one minor error this is the ignition circuit of a classic car with non-ballasted coil:



This is the basic circuit for all Smiths instruments (includes the other RVC kind of tachometer)



This is one of the possible methods of fitting a relay-style battery isolator.


With the information supplied by you, that's the best I can do for you with the information you have supplied.

[checkrail]

Thanks Bill for all the info. I thought that I had solved the latest problem, the terminal was off the ignition switch in the starting position but still no ignition light, and no power at the coil

[checkrail]

I know that the ignition circuit goes via the tacho and that's where the problem must be so:
no ignition light, there's power from the ignition switch starting terminal.
no power at any of the voltage stabiliser terminals
no fuses have blown no power to the rear screen
of course the fail light is on all the time but the priority is getting the ignition circuit back

It's such a struggle to get to the back of the tacho but I'm sure the connections are o.k.

p.s. I no longer have the anti-theft switch John

[checkrail]

I have managed to loosen the tacho mountings off enough to check the wire connections, they are all tight.

Where do I go from here?