WANTED - Classic Mini automotive electrical help

I need some electrical help with my Mini. I’ve got a series of issues to work through and this is the best place I can think of to ask.

The time has come. Everything is finally installed and in place. The mini is oil tight, coolant tight, and electrically grounded. All electrics are hooked up. That being said I do have a series of issues that I need to fix before I can get it inspected in my registration renewed. Below is a bad status list for all components affected:


Headlight switch:

  1. ✓ gauge lights work
  2. ∆ Left rear amber lit
  3. ∆ rear running lights not working
  4. ∆ brake lights not working
  5. ∆ number plate lights don’t work

Hazard switch:

  1. ∆ rear brake lights flashing (should be amber lights)
  2. ✓ all other lights flashing

Left Stalk:
3) ∆ LH blinkers function except back left (rear brakes blink)


Hope you got that Lucas smoke injector and several refill canisters before the plague set in … may be harder to find than TP & hand sanitizer.

On a more serious note: That many things out, could be a ground issue. The reason I say that is seems rear light issue and it seems when ever I do trailer lights … it’s always a ground issue.

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What wiring have you cut/spliced/unplugged/etc since the swap? Sounds like just a couple of crossed wires.

Do you have a wiring diagram for the car?

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I replaced the entire loom with a brand new one (not new/old stock). The only things still original are the smaller wire clusters at the lights themselves.

Thinking either relay for indicators or ground.

MINI 1000 SALOON - MINI SPECIAL 1976 ON - PAGE 86-5.PDF (126.9 KB)

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The behavior is literally like the wires are crossed so it’s very odd

Ok, lemme have a go at the break lights…

We know they turn on any time the left turn signal should be on, they flash, and the don’t turn on when the brake pedal is pressed. Both act in unison.es

So the issue is likely with the Green/Purple wire run from the rear of the car forward, since that’s the location that can cause both lights to turn on. My guess would be that it was accidentally connected to a green/red wire which is used for the left hand turn signal. If they were swapped I would expect issues with the left turn signal (notably it would not blink).

Yes I actually meant crossed wires this time. Cars pretty much never switch the ground on or off so imho as long as a light turns on it has a good ground. There are some indicators in the mini that have switched grounds but all the exterior lighting is tied straight to ground.

I did fix the brake lights somehow (they still blink, but they work with the brake pedal now)… I don’t know what I did to fix them though :neutral_face:

I’ll have a look at the wires tomorrow. Storage place closed so I had to leave. Thank you!

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Nice :stuck_out_tongue:

Check and see if any of the indicators turn on with the brakes now. Also see if you can pay attention to the brightness of the lights to see if anything is accidentally wired in series (should be notably dimmer if they are). Good luck!

Indicators don’t turn on with the brakes. Pedal press and brakes come on as normal.

Always, always prove you have good, solid ground between each lamp socket and some proven ground point. Any system that has two incandescent light bulbs sharing one ground can be really good at back feeding from one circuit to the other, and causing other bulbs to light or dim, or do other odd things. And depending on ambient lighting, you don’t always notice what is lit at 1/4 power, full power, or other odd states.

Proving ground will just make so much other troubleshooting make more sense.

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