Help with Main Beam PLEASE !!

[brett]

OK, I'll describe my problem as well as i can, i hope !
My car is a 1955 Series 2 facelift.

With the headlights on, ( switch pulled out to second click ) if i press the dip switch it turns off the dip beam but does not turn on the main beam also no main beam warning light in speedo ( i have replaced the tiny bulb ).
If the dip switch is then pressed again ( to, in effect go back to dip beam, nothing happens, the dipped lights will come back on when they feel like, or not at all
The side lights, brake lights, number plate light, speedo illumination and indicators all work fine, as do the dip beam's until the main beam is tried.
I have replaced both headlight bulbs with brand new ones.
Another problem is all my wires are braided and not colour coded anywhere which doesn't help !

I have read a lot of threads on here about headlight problems but i can't find anything similar to this !

Could it be a fault in the dip switch ?

[chesney]

I had a similar fault in my '58 (same setup), it was the dipswitch.

[bmcecosse]

As above -have a look at the wires where they attach to the dipswitch - and the switch itself. To test - join each cable in turn to the headlamp feed wire (would have been blue at one time) to check the lights otherwise work. A good blast of WD40 into the switch may clear it - possibly just jammed up with carpet fluff!

[brett]

Many Thanks for the replies
The dip switch is actually unscrewed and will be looked at in more detail soon !

I did what i said and started from scratch, and i'm SO glad i did !!! How the car's not been on fire is beyond me
Everything joined to everything else, what a mess. The main culprit was the after market flashing indicator set up which has now been completely removed, so just the semaphore's for the time being then !
Behind the speedo was awful with burnt wires touching each other and bare ends so after making loads of careful notes and drawings i've removed the speedo and the heater and started to replace all the dodgy wires, not going to be a quick job, i'm wondering if i should just buy a new loom...............

I was wrong by the way, there are some colours on the headlamp loom wires, although very faded, the sidelights are a red wire, and there is a burgandy wire for an earth, most of the rest seem to be dirty white with a hint of greeny/blue though, if anyone knows which one is which i'll be forever grateful

Would the dipswitch being faulty also explain why the main beam warning light won't come on no matter what ?

[bmcecosse]

See the wiring diagram at the head of the electrical section - print out and laminate it for working on the car. Yes - the blue light gets its feed from the dipswitch - same as the main beam filaments.

[mike.perry]

The main beam problem is the dipswitch is worn out and is not clicking over properly. I had the same problem, a bit disconcerting when you dip your lights for an oncoming car on an unlit lane and your lights go out!
Fit a new wiring loom whilst you still have a car to fit it to. You can still have indicators and trafficators, see http://seriesmm.mmoc.org.uk Tech Info, Trafficator and Indicator wiring diagram. You can have it built into a new loom together with any other accessories

[bmcecosse]

The switch will just be jammed with carpet fluff.......it doesn't get enough use to wear out!

[DAVIDMCCULLOUGH]

I worked on a friends headlights and found the 3 way connector that comes from the behind the dipswitch out into the engine bay that all the insulation on the 3 way had melted and that the wire were touching. Probably a good idea to replace any old bullet connectors that are still under the dash as the rubber over times does perish and looses it insulation.

if you are fitting a new loom which has just been done on my friends car, do add a fuse into the sidelight circuit, as the original non fused set up caused his sidelight wire to melt all the way up to the switch........ i really must fit the new loom to my MM, its been in the boot about 4 years now.......

[mike.perry]

Dipswitches do wear out. Been there, Seen it, Done it.

[bmcecosse]

It's so rare to get on main beam these days - it's hardly worthwhile having the facility! Mine is original - 50 years old and still working perfectly........

[whyperion]

Duuno where BMCEccosse is driving these days, many local Lancashire dual carriageways have their lights switched off after midnight and dip is too feeble to cope with 50mph crusing, likewise the small country lanes need the solid stone walls visible.

[bmcecosse]

But there is always something coming the other way!

[chickenjohn]

Take the bulb out and test the terminals on a battery, (from memory so forgive me if wrong) facing headlamp, left terminal is earth, top is main beam and right is "normal' headlamp.

It is possible for main beam to burn out and the low beam to still be working on a sealed beam unit.

[rayofleamington]

Behind the speedo was awful with burnt wires touching each other and bare end

That's only the damage you can see! I'd really recommend to go for a new loom.

[grantstew8]

This gives me a starting point as there is no obvious broken wiring or connectors that have come adrift.
High beamed worked and no low beam, so drove home on brights and managed to choose a quiet road. Did annoy a few oncoming cars but given the option of compete darkness .....
Thank you and I'll keep you posted...

[grantstew8]

Unbolted the foot switch, wd40 and a few wiggles and hey presto back in action. Thanks for the pointers.