10 replies to this topic

[supersimono]

Hi all,

Another headlight issue but I’ve tried everything I can and really stumped as to what the problem is .I’ve got my wedding in5 weeks and need to get it running,MoT and taxed.

I’ve got a complete new loom, new indicator stalk, dim/dip resistor removed with bypass, WIPAC LED headlights.

I have a working headlight, side light, dipped beam and flash, but when the indicator stalk is pressed forwards for main beam I have only sidelights.

Going by the wiring diagrams, I should be receiving power from the lighting switch to the indicator via the blue wire. I have no continuity at this point from the switch so therefore nothing going to the blue/white. I have checked the stalk (bought a new one in case it was faulty) and I know that when main beam is selected the stalk is contacting.

I’ve got a main beam relay fitted which is working as I hear this switching on/off when using flash. I’ve taken a feed from the bullet connectors behind the grille (blue/white) as my low voltage and the taking power from the starter motor with a 15A fuse.

Am I missing something in this setup as I can’t figure it out

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[sonscar]

If you have dip beam then the blue wire must have power.Are the LEDs wired correctly?Steve..

[supersimono]

I believe this is correct:

Earth: black - white
Dip: blue/red - green
Main: blue/white - brown

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[Spider]

Sounds like there's no power on the Blue  /White Wire.

Issues like this I usually start with a meter or test lamp at the connector for the column switch. Make a good earth connection somewhere for your Tester turn the head lamp switch on, check the tester by putting a probe in to the harness side of the plug on the Blue wire. If the tester is working, then try it in the Switch side of that plug, then keep working from there, even checking the harness side if that plug. Then move in to the engine bay.

If you are not getting it at the plug, but it does work on flash, then I'm inclined to suggest the combination switch is the issue, you might find the Main Beam contact needs a small bend. If making adjustments here go easy, it's quite easy to ruin the switch.

Check too the wires are properly plugged in to the back of the combination switch (yes these plug in here too).

[supersimono]

Agreed that there is no power going down to blue/white.

Is my assumption correct? With the lighting switch on the dash ‘on’, I should always have power/continuity to the stalk as it is blue to blue? that’s the bit I think is the issue as flash works but main beam has nothing and I don’t believe there is anything else in that path that changes? Only thing I can see if the blue/red connection on the stalk disconnects.

if I put a 12V feed to the main beam relay (pin 86) I then get main beam.

I don’t think it an issue with the stalk as it is brand new and it’s the exact same issue with the old one

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[cal844]

What year of car? Late carb cars (1990 onwards) have 4x inline fuses behind the speedo binnacle

[cal844]

What year of car? Late carb cars (1990 onwards) have 4x inline fuses behind the speedo binnacle.

My suggestion is to buy yourself a power probe with voltage readout, a very useful tool in diagnosing issues like this.

I would start by checking for power at the switch (I cut the stabby point from a sewing needle and fit that into the back of the connector as a backprobe) then put the tip of the power probe to the sewing needle and record the reading (write it down) and repeat the test ay the stalk, you may find it's one of your new connections that havent been crimped properly (it happens but not mocking you!)

I hope this helps. If you wish I can have a look at my 1993 car to check wiring and routing etc. Any questions please post in the chat

[Ethel]

That dim-dip label will explain a lot I reckon. It should turn on dip beam if you have sidelights & the ignition both turned on. It was originally supplied via a resistor to do the dim bit. The bottom image in the first post looks like the relay has been removed & replaced with that jumper wire.

 

What wires on the loom side is the jumper connecting?

[sonscar]

Do you really have dip beam?There always seems to be confusion about lights.There are two states(ignoring dim dip)dip and main.If you really do have dip then the fault is the switch or after it.Steve..

[supersimono]

I think I may have figured the problem.

I checked my old loom for continuity between switch and stalk to see what I should be reading. My understanding of the switch and stalk is that blue is always connected to stalk but depending on which mode (normal, flash or main beam) it powers a different circuit. For main beam the stalk disconnects the blue/red and powers blue/white only.

I checked the plug connections of the new and old loom where the stalk fits into as the only instance I have an issue is main beam, I have continuity between the switch and the stalk as expected. The old loom I believe is correct as I have continuity in all lighting positions from switch to stalk. Blue connects to blue, blue/white to blue/white and blue/brown to blue/brown.

On the new loom however, blue on the indicator stalk is connected to blue/brown on the loom and blue/brown on the stalk is connected to blue on the loom - so this is the reason why I have no power?

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Edited by supersimono, 27 July 2025 - 02:51 PM.

[Ethel]

I think  you're right. 

 

The solid blue from the light rocker switch should supply the stalk and the high beam, via the blue/white. The blue brown supplies the dim-dip relay from the stalk in order to power the dip beam beam when the rocker switch is in the headlights position. There's an alternative permanent live (Brown/Orange) to the dim/dip relay, via the dimming ballast resistor that would only get connected by side lights & ignition both being on.

 

Without the relay you need the solid blue feeding the stack and the Blue/Brown jumpered to the Blue/Red at the relay socket.