Fail MOT today

[wazcov]

Well she failed her MOT very quickly today. So quickly in fact that I didn’t get charged thankfully. Headlights come on but no sidelights and no rear lights. Fogs work, indicators work, main beam works, no side or rear. 

[alanrichey]

Probably just a fuse as the headlights are on a different fuse to the rest of the lights.  Don't ask me which one though   I actually replaced many of my fuses with the ones that light up when they fail.  Makes tracking them down much easier.

[Jonty Wild]

18 minutes ago, alanrichey said:

Probably just a fuse as the headlights are on a different fuse to the rest of the lights.  Don't ask me which one though   I actually replaced many of my fuses with the ones that light up when they fail.  Makes tracking them down much easier.

That's clever where did you get those from?

[AndyW]

If your car still has the original RH wiring loom, the side lights were all powered by a permanent live from the light stalk, which went to a 10a fuse and then out to all lights through red wires. Hopefully straight forward to track down.

[IanS]

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Comes in packs of 10. Select fuse Amps to suit.

[Jonty Wild]

And the light when they are working or when they are not?

[alanrichey]

When the fuse blows the little LED on top lights up.  I assume they are wired in parallel so that the amps normally go through the fuse (zero ohms), but when that goes open circuit the current flows through the LED.   Clever stuff

[wazcov]

On 7/4/2025 at 2:42 PM, AndyW said:

. Hopefully straight forward to track down.

There’s nothing straightforward about the electrics in this car…

 

I tracked a blue/red labelled dipped which I tested had 12v on main beam and 0 at dipped and sure enough seems to control main beam.

 

i tracked a blue/white labelled main which had 0v on main or dipped settings.

 

I presume the labels are incorrect and the blue/white is meant to be dipped and is the failing one. Looks wired up correctly so maybe a stalk issue

[AndyW]

In common uk wiring and the original part Ford loom supplied with the Superspec, blue/red is used for dipped beam, and blue/white for main beam, between the switch and the bulbs.

But you said your front and rear side lights weren’t working. Those are a separate circuit to the headlights. They should be a solid colour red wire feeding all of those and the instrument illumination.

Are you still using the original Rover column stalk switch for lighting?

[wazcov]

6 hours ago, AndyW said:

In common uk wiring and the original part Ford loom supplied with the Superspec, blue/red is used for dipped beam, and blue/white for main beam, between the switch and the bulbs.

But you said your front and rear side lights weren’t working. Those are a separate circuit to the headlights. They should be a solid colour red wire feeding all of those and the instrument illumination.

Are you still using the original Rover column stalk switch for lighting?

It’s on the column but not sure if original as I have a spare column set in a box that may have been the real original. Looks like a rover one though

[AndyW]

This is the RH supplied Rover column light switch if it matches yours? When you’ve checked all the fuses for the lights are ok, then check the wiring at this switch. No loom connector was supplied so you had to use small female connectors to wire directly to the exposed pins on the switch base. Mine were not very secure and on occasions came off or moved and touched each other. There are 2 groups of pins. On my car they were wired as follows:

3 pins for 12v power from flasher relay, to left & right indicators

6 pins for lights:
1: 12v for sides
2: to main beam
3: to sidelights
4 & 6: 12v for headlights
5: to dip beam

Check yours are all intact.