Morris Minor Owners Club

First thing I did when I bought my Traveller, was to change the sealed-beam units for halogen. The odd thing is, that while both dipped beams are equal, on main beam, the near side light is quite dim compared to the off side. As the earth is common, it can't be that I would have thought. Any suggestions? Dodgy bulb perhaps?

The earths should not be common, but both earth to the inners wings via a bullet connector. They do tend to corrode and get full of gunk so a clean up is probably all they need.

minor_hickup wrote:The earths should not be common, but both earth to the inners wings via a bullet connector. They do tend to corrode and get full of gunk so a clean up is probably all they need.

I meant that the earth is common to both the dipped and main beam on the same side - the implication being that if the dipped beam is OK then the dimness of the main can't be caused by a dodgy earth....

Oh I see what you mean, its probably the bullet connections on the offside.

I'd be checking the bullets both sides, as it sounds like it's the wires from the double female bullets on the offside into the bullets on the nearside that're causing the problems.

I say checking, I mean popping them out, quickly sanding thm shiny, then popping them in and back out the female bullet a few times to get a good contact. Maybe I'd even go so far as to wrap some wet and dry round a small screwdriver and clean up the insides of the female bullet connectors.

I wouldn't dismiss the earth completely as the main beam takes more current that the dip 60w vs 55w with standard H4 bulbs.

After cleaning all the bullets (replacing them would be better with brass ones and new connectors - how old are the originals?) wipe some vaseline on them to prevent future corrosion.

I had just that problem too. It was with halogens working through relays and std earth points. Bizzarly it was the earth on the other side that was the cause. A bit of sand paper to get some bright shiny metal both in the bullet connectors and under the earth to body point and all was well again.

Roni wrote:I had just that problem too. It was with halogens working through relays and std earth points. Bizzarly it was the earth on the other side that was the cause. A bit of sand paper to get some bright shiny metal both in the bullet connectors and under the earth to body point and all was well again.

Cleaned up all the connectors, no joy. Even ran the main beam direct from the battery - STILL dimmer than the other side. Swapped bulb and reflector. No joy at all.
Any more suggestions?

If changing the bulb and reflector and feeding the 'live ' bulb connection straight from the battery had no effect then the fault must be in the earth return side. Try an alternative earth connection to check for improvement. As Richard said above the main beam takes more current
than the dipped ,so you do have a connection, but it may not be good enough for the main beam.

if you have tried them BOTH straight from the battery with the same piece of wire then the fault is with the headlight. if you swap the bulbs over and test again if the fault follows the bulb then the bulb is at fault if it stays then the inside reflective surface could be dirty/tarnished or even the inside of the glass.
are you testing with a light meter? or is the test by perception?

Try swapping the bulbs over and see if the fault goes with the bulb or stays with the wiring.

Also while you have the headlights out measure the voltage between a good earth and the live side of the bulb. Do this with the lights on so that its on load. If you don't have a good 12 volts there its in the wiring somewhere on the supply side conversely if you do have 12 volts there check the side that goes to earth. I have avoided saying positive or negative because that depends on which way round your battery is.

If you do as Roger says and find a low voltage at the bulb, then you can use the voltmeter to measure the drop along specific sections of the wiring and thus pinpoint the fault. The voltage across each wire/terminal should be as close to zero as possible - if you see a few volts when you put the meter on each side of a connector then it needs cleaning.

Thanks to all who replied - seems it was a combination of not-very-good connections and a dodgy bulb connector...(the bit the bulb plugs into....)

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