Very dim headlights when dipped

[johnt1]

On our recently acquired Bulldog Mk 4, we have eventually got the sealed beam headlights to work.  On main beam they seem OK but on dipped they are very dim/dull.  Does anyone have any suggestions please?      John

[istreatf]

Hi John and welcome to the forum.
If you look back on virtually any question on this forum on electrical problems, you will find me replying and usually ranting on, being usually quite tunnel minded about the solution to the problem. This centres around the earth. Not the global one, but the metal one that runs underneath your plastic body. The plastic body is the problem in that it replaced the donor metal one, and therefore additional earthing points had to be made in order to run any electrical equipment in your car. So the solution to your problem is the earth. You have to be very single minded about this - the problem is the earth. If you cannot find any earthing problems, then the problem is the earth. Maybe one of the earthing points is not quite good enough - but the answer will be the earth. Unless of course the sealed beams are so old that they are just dim - check by running some wires directly to the battery - both live and neutral - and if they are brighter, then guess what? You have an earth problem. If you find all your earthing points are good, are they powerful enough? Your lights are probably 45/60 watts, so take 4 - 6 amps each - so I would make sure that your earthing leads can handle at  least 10 amps above the sidelights, indicators, horn and whatever else you have hanging off them. Lets say 30 amps. That is a big bit of wire.
Good luck and please let us know how you get on.

[pccthebreed]

What on earth is he on about?? Of course Ian is probably right but I have had similar problems with my MKIV and it was down to the lighting stalk making very poor contacts. By all means run some new earth wires but if that doesn't cure it try running a temporary light switch and see how you get on.
Good luck.
Keith

[Mahin]

Well, if it isn't earth connections, it is because old cars tend to have electrics from the Prince of Darkness, Joseph Lucas. Or his imitators.
Ergo, problems with switch contacts.
For some humour, see here:
http://www.mez.co.uk/lucas.html
Do check out the wiring loom replacement smoke thread.

[Nigel Haldane]

I would usually say earth but you have said eventually got the lights to work. Have they been wired correctly one connection is common to both filaments this should be earthed. If this is exchanged with the feed to the main Beam it will work OK but the dip will have to go through both dip and main. If you turn on the light on dip and you can see both the filaments glowing this would be the cause. Hope this helps Nigel

[johnt1]

Thank you all for your suggestions and we will try them all until we get a result. I think the switch on the stalk is a bit dodgy as we had to mess with the contacts to make the sidelights work . It may be the original Cortina one-there are about ten cables coming from it so it may be difficult to wire up a temporary one even though I worked for the Prince of Darkness in Middle Earth ( Great KIng Street in Birmingham) in the late 1960's/1970's. At least the headlights come on now.When we first had the car the sidelights came on when the headlights were switched on. I will let you know how we get on but with the weather and work and my assistant (son) gone climbing Snowdonia  it could take a while. I just hope we can get an MOT certificate before I get a birthday card from the Queen  Regards , John.

[pccthebreed]

Hi John,
You can take the stalk assembly apart enought to give it a good spray of switch cleaner, I actually used carburrettor cleaner, and this might make enough difference to confirm that it is dodgy contacts. I was lucky enough to get a replacement off of ebay for a tenner . Another problem that I came across was poor connections in the loom as my loom seems to be made up of many pieces and the connectors have taken some strain when work was being done on the car so it might be worth checking them.
Regards
Keith