Head Lights

[dwatson98]

My head lights work on dipped beam, you can flash them 3 will work 1 high beam not working but when you put high beam on permanent they all turn off could that be a bad earth on the one not working
regards David

[GrahamFountain]

Got a volt meter?

Is the main beam warning light on the dashboard on with either flash or high beam on permanent, or not?

Here's a cut down to just the headlight circuit. Sorry about the quality, it's a .jpg of a paint edit of a screenshot of a .pdf document that's a scan of the 1980 manual.

I think you're going to have to take some voltage measurements at various points on this circuit, some of them on the back of the switches in the steering column binical.

I'd start with the voltages on the pin on the column light switch (21) where the blue (U) wire goes, and the pin where the purple wire goes, when the lights are in dip, and then when they are in main beam. The latter being when, if I read what you wrote correctly, all the headlights are off.

Also, have you checked the bulb where the main doesn't light? Could that part of the problem be just a bulb/filament gone?

Graham

[soe8m]

When they are totally off at high beam and not even something is glowing in the lampunits you have one faulty bulb and one faulty column switch.

Jeroen

[Carledo]

What Jeroen said! ^^^^^

Steve

[GrahamFountain]

Looking at the circuit diagram, it does seem like the only possible cause is the main/dip/flash switch has the contact that should connect the blue wire to the blue and white wire failed. But the contact connecting the purple wire to the blue and white wires is still working. And one of the bulbs is failed.

But that's jumping to a conclusion that measuring the voltage either side of the contacts with flash and mains on would show. And it's a lot cheaper to measure than to buy a new switch. Measure once and cut twice. No, that's not right. Oh, what the...

Then again, I too can jump higher than a mountain.

Graham

[soe8m]

That wasn't a diagnose but recognizing someting what I have seen 100 times before.

All Dolomites, Stags, 2500's have the same switch and 4 main beams and all these have the same trouble of melting the plastic around the contact that has the blue wire on. The blue white contact is the moving part and moving the stalk the other way it connects to the purple wire contact and then the lights flash.

This problem was already around when Dolomites were new I believe and that's why a lot have relay's fitted on the mains. Good switches are rare and I regularly get the question to sell LHD type switches to fit on RHD cars to have the standard layout but I do not sell as a few off all I have are decent and most are already melted or not working at all. The RHD versions obviously the same. So when you have or find a decent switch, save it with some relays because good original ones are rare.

Jeroen

[GrahamFountain]

If it is the switch contact that has failed, not a wire lead to/from the switch that has broken, etc., it is just possible the contact has only gone too high resistance to carry the current for the bulbs direct. In which case, it just might drive a relay that could then drive the bulbs indirectly.

It may not be much of a chance it will drive a relay, but if it does, it saves replacing the main/dip/flash/indicator switch, which ain't that cheap [https://www.ebay.co.uk/itm/232450675596 ... SwOPhgHRKF] and is a bit of a pain to swap.

Even if you do have to replace the switch, it's still worth considering adding relays to drive the mains and dips, as it takes a lot of load off switch contacts, and isn't that hard to do (don't mention Scotch Locks as an option for splicing the relays in, it upsets Steve).

Graham

[Carledo]

(don't mention Scotch Locks as an option for splicing the relays in, it upsets Steve).

Graham

Thanks for your consideration dude (or was it just another red rag to my bull?)

Why would anyone do something good (fitting relays) but do it so badly (using scotchloks) that you ruin the effect?

Scotchloks are the spawn of Satan!

Steve

[killysprint]

If it is the switch contact that has failed, not a wire lead to/from the switch that has broken, etc., it is just possible the contact has only gone too high resistance to carry the current for the bulbs direct. In which case, it just might drive a relay that could then drive the bulbs indirectly.

It may not be much of a chance it will drive a relay, but if it does, it saves replacing the main/dip/flash/indicator switch, which ain't that cheap [https://www.ebay.co.uk/itm/232450675596 ... SwOPhgHRKF] and is a bit of a pain to swap.

Even if you do have to replace the switch, it's still worth considering adding relays to drive the mains and dips, as it takes a lot of load off switch contacts, and isn't that hard to do (don't mention Scotch Locks as an option for splicing the relays in, it upsets Steve).

Graham

Rather than mess about, Jeroen makes a great kit to add relays for lights, horn and an electric fan and a new front loom. Relatively easy to fit even ham fisted oaf like me. really neat and tidy. Class bit of kit, integrates with the rest of standard wiring loom seamlessly. Nice to know that you have all new wiring powering the lights too.

[Graham.Fountain]

I have enough of my own bêtes noires.

But the one place I might think about a Scotchlock in this case would be splicing off the big fat brown wire to the main light switch, to supply the power feed inputs to the relays. That's the one wire that doesn't actually need to be cut; where the blue and white and blue and red wires do need cutting anyway to connect to the controls and output of the relays. Also, because I'd always mount the relays under the dash where they have the least possible impact on the car, other than taking the load off the light switches, (and you can then feel the relays to see if they operate when you work the switches) that one Scotchlock is in the best possible place one could ever be.

But then again, I've put a second fuse box in the engine bay and feed the main and dip relays each from their own fuse. So I don't have a connection to the big fat brown wire. I know putting fuses in the supply to the lights is a six and two threes: it adds something that can go wrong, so it will, and it will always go wrong whenever it will cause the most problems (Murphy was an optimist). But I just felt it was better than not.

I also get the desire to mount the relays close up to the bulbs so they can also reduce losses in the cable runs to them - big fat wires from the battery, etc. But I don't care about that side of it. Only saving the switches from the current to run all them lights.

Graham

[Graham.Fountain]

Rather than mess about, Jeroen makes a great kit to add relays for lights, horn and an electric fan and a new front loom. Relatively easy to fit even ham fisted oaf like me. really neat and tidy. Class bit of kit, integrates with the rest of standard wiring loom seamlessly. Nice to know that you have all new wiring powering the lights too.

Well, perhaps. But the second thing is to check if there's even the merest hint of the possibility of a chance of not having to replace the switch. Looking at the switch and, probably, measuring the voltage on the blue and white wire, as a min, with the switch in the flash and main light positions. Worth measuring the inputs as well, though probably not as important unless the fault is one of them weird ones. But they do happen.

Graham

[soe8m]

If it is the switch contact that has failed, not a wire lead to/from the switch that has broken, etc., it is just possible the contact has only gone too high resistance to carry the current for the bulbs direct. In which case, it just might drive a relay that could then drive the bulbs indirectly.

It may not be much of a chance it will drive a relay, but if it does, it saves replacing the main/dip/flash/indicator switch, which ain't that cheap [https://www.ebay.co.uk/itm/232450675596 ... SwOPhgHRKF] and is a bit of a pain to swap.

Even if you do have to replace the switch, it's still worth considering adding relays to drive the mains and dips, as it takes a lot of load off switch contacts, and isn't that hard to do (don't mention Scotch Locks as an option for splicing the relays in, it upsets Steve).

Graham

That wasn't a diagnose but recognizing someting what I have seen 100 times before.

All Dolomites, Stags, 2500's have the same switch and 4 main beams and all these have the same trouble of melting the plastic around the contact that has the blue wire on. The blue white contact is the moving part and moving the stalk the other way it connects to the purple wire contact and then the lights flash.

This problem was already around when Dolomites were new I believe and that's why a lot have relay's fitted on the mains. Good switches are rare and I regularly get the question to sell LHD type switches to fit on RHD cars to have the standard layout but I do not sell as a few off all I have are decent and most are already melted or not working at all. The RHD versions obviously the same. So when you have or find a decent switch, save it with some relays because good original ones are rare.

Jeroen

[Graham.Fountain]

it is just possible
It may not be much of a chance

But at the cost of a new switch and the trouble of fitting it, assuming that is the problem, nearly any avenue is worth a drive up, even if it's just for the sightseeing.

Graham

[dwatson98]

thanks for all the help ill have a look regards David