Indicators/Brake Lights Issue

[Stourbridge_moggy]

Hi all,

hoping someone can advise me on an issue I'm having with both indicators and brake lights.

I've just completed a semi- restoration where a majority of parts came off, except the engine bay that remained untouched, including wiring

The issue(s) are - indicators. I've had these working and flashing great. I've had to replace the flasher unit twice and again today when I went to work on it, no indictors. I'm thinking something is burning out the unit?

Second problem, that I'm thinking is part of the indictor problem, is no brake lights.

All other electrics work, including front and back lights. and when the indicators do work so does the stalk.

I have a relay fitted, and its been modified with the orange indicators on the front. The back lights have the indicator at the top (with amber lens) then the two filament bulb below. I'm thinking that the wiring was set up where the same bulb flashes and brakes, or flashes and rear lights (can't remember which is correct) but then changed to a separate indicator?

As a means of trying the brake lights/testing the switch, i disconnected the brake switch and ran a cable to the connection (left/right split) in the boot that leads to the lights (also disconnected from the cable that runs under the car). I was getting power through this temporary cable but it 'sparked' when i tried to connect it to wires in the boot.

When I tested the back light 'cluster' out of the car all bulbs worked fine and wasn't shorting. Any electrical parts I took off (only front and rear lights/indicators and speedo) were photographed before so i have a record of how the working wiring was set up. So I'm thinking that perhaps an earth that I took off but didn't photograph is the problem.

No doubt, it's a simple fix somewhere, but where? I'm wondering if anyone knows of a source thats affecting both indicators and brakes.

Fuses are all good, and everywhere I test I'm getting current.

I think that's everything i've noticed, hope this gives enough info. thanks in advance

EDIT: as i was reading that back, it came to me that if when i touched the powered cable from the bypassed brake switch to the brake bulb wiring in the boot, and it sparked, both must have current going through them. is it possible that power from either the indicator or rear light is running back up the brake bulb wire? even though both are not on? or could it be power is running up the earth cable? causing a short and affecting both indicators and brakes? Would a short in one rear light cause both sides not to work?

Phew sorry about how long that was! not that anyone has anything better to do

[Stourbridge_moggy]

After a bit more reading around, I see there's different combinations of set up for indicators/back lights. As I mentioned before, the car had the joint indicator/rear light set up before being updated. But a post from 2016 by charlie_morris_minor mentions his car has been updated to later rear lights also, and the relay indicator is just bypassed.

I wonder if I could do this also, as mine has the flasher cylinder too?

If I could, would it be a case of simply connecting the matching wires in and out of the relay indicator?

I'm beginning to think that the relay has burnt out/is shorting or something on those lines.

Thanks again

[Stourbridge_moggy]

UPDATE

I re-wired the indicator system, bypassing the relay indicator and all works well.

Now just the break lights. I have power up to the point of the connection when it splits left and right (in the boot). I've bypassed the brake switch.

Yet when I do connect the left and right split, neither side works. I have impedance between the splitter and the bulb terminal.

The only difference between the two sides I can find is left hand side, I get impedance when testing between earth and a) the cluster casing, and b) both bulb terminals (lower bulb). on the right side I get impedance from the cluster casing, and only one bulb terminal - the rear light terminal.

I've separated the splitter as to try each side individually and still no light.

Still a bit stumped on this one, any ideas? thanks +

[Stourbridge_moggy]

Solved.

So after rewiring both back light clusters, I was able to track the issue down the the earth connection inside the boot from the left hand side cluster was slightly loose. It seemed the earth was finding its way back through the rear light cable.

But all working, now on separate circuits.

[shoebone]

Well done for fixing the problem and thanks for keeping us informed. It sounds like your car has been modified from standard and this makes it difficult to help with your problem. Bad earths can manifest themselves as all sorts of weird goings on but is a relatively easy fix and is one of the first areas I check when I get weird stuff happening

[Stourbridge_moggy]

Well done for fixing the problem and thanks for keeping us informed. It sounds like your car has been modified from standard and this makes it difficult to help with your problem. Bad earths can manifest themselves as all sorts of weird goings on but is a relatively easy fix and is one of the first areas I check when I get weird stuff happening

and modified without using a correct wiring loom. mismatching colours everywhere.

i wonder if anyones ever drawn up a diagram of all the earth points. that might be quite helpful as a starting point.

[oliver90owner]

i wonder if anyones ever drawn up a diagram of all the earth points. that might be quite helpful as a starting point.

I expect every earthing point is shown clearly on the workshop manual wiring diagrams.