Sidelight / RH indicators confused.

[Blaketon]

Last weekend, I put the battery back into my father’s MG Midget, which I hope to turn over and fire up soon. It has a battery cut out, that is bypassed by a fuse and to start with, I am relying on that, to check the smaller items.

The fuse hasn’t blown, so there are no short circuits so far and all has worked (Like the new electric cooling fan, which has auto and manual switching), aside from a problem with the sidelights and right side indicators. If I operate the left indicator, all is well but if I operate the right side, the right sidelight, rear lights and number plate lights flash with it (To the apparent displeasure of the flasher unit). If I put on the side lights, the right hand indicators and warning light (They are separate for left and right on the Midget) all come on (Not flashing). On my father's Midget, the front indicators share the same fitting as the side lights.

I probably won’t get chance to look at it before the weekend but I am thinking it could be an earthing or switch problem. Any auto electricians among us, who have come across this one before?

[Sleeper]

Bad earth right rear...

John ;-)

[geoberni]

Typical symptoms of an electrical circuit finding the lowest resistance path to complete the circuit.

As Sleeper/John says, very likely a quite high resistance to 'earth' at the right rear light unit.

You've not said what sort of light cluster it is, i.e. the period of the car. I'm not clued up on Midgets, but I think even the early ones were separate lamps for indicator and side lights.

But I'll ask the question, are the Indicators and Side/Rear lights separate bulbs? Because if there is a shared bulb anywhere it is possible for the wire filament to break and drop across to the other one, causing the circuits to interconnect.

[Blaketon]

The MG Midgets had the same kind of rear light as the MGB, see https://www.oldclassiccar.co.uk/photos-audlem-06/71.jpg . The indicator is on it's own, whilst the brake and side light share separate filaments in the same bulb. I've established that it's only the rear light bit that's coming on with the RH indicator.

[geoberni]

So as I understand it, what we have is:
Front Side Light,
Rear Side Light
Rear Indicator
RH Number Plate Light
RH Indicator warning light

....all working at the same time, either steady when sidelights are one, or flashing if indicator used. You've not said which if any are at full brightness and which are a bit dimmer.

I would remove the covers from the front and rear RH side and then see what happens if you take out each bulb, replacing one before removing the next. It might give us a clue.
I suspect we're going to end up with it being a bad earth of the RH rear light cluster so the respective circuits (Side and Indicator) are going to earth via the number plate lamp and the front sidelight.

Do come back and tell us what you find....

[Blaketon]

Sorted it. I only get time to look at it on Sundays (Late start today on account of power cuts), so I began at the front right corner, checked the earths of both sidelight and indicators. Both were OK, so I traced the wires back inside the car and bingo. It seems my father used one double connection instead of two singles. Since he's not done this elsewhere, I just put it down a silly error.

Thanks for all the suggestions, with which I was forearmed, for what I feared might have taken much more than five minutes. Now I can proceed to get the car started.

[geoberni]

Well that'll certainly do it!
Glad you found it.
Sorting out a silly error is a lot easier than finding it was due to corroded earth points.
Dad may have thought it was a side by side connector pair, rather than a 4-way item.