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MG MGB Technical - Headlights/dipswitch confusion

The headlights (both dipped and full beam) on my '68 B don't work. The sidelights and panel lights work fine.

Wiring diagram in hand, I suspected the lights switch, which is of the pull-type, so I removed it. Bypassing it by connecting the brown to the blue and red wires did not solve the problem.

So I had a look at the dipswitch (or rather, what I believe to be the dipswitch, on the steering column) and checked that the blue wire there was connected to the blue wire at the lights switch, and it was.

However, confusingly, the blue/white (full beam) and blue/red (dipped beam) wires at the dipswitch are *also* connected to this blue wire, regardless of the position of the stalk!

I'm not sure what to make of this - isn't the stalk supposed to make the connection between the blue and blue/white full beam wires only when full beam is turned on?

Help very much appreciated!

Cheers,

- Matt
Matthijs van der Meer

Hi Matt...

Do the main beams come on when you use the flash position on the main / dip stalk ?.

If they don't, I suggest you check that the headlamp earth wires really go to earth.

HTH.. Don
Don

It is. Track 12v through the brown, blue, blue/white or blue/red to the connectors near the right-hand headlight. Does the main beam tell-tale light from either the light switch or the flasher? If it glows on both dipped and main but the headlights don't then the ground could indeed be the problem.
Paul Hunt

I'm not all that sure about the electrics in this, but do know that on my 69MK11 the dipswitch is a foot button on the firewall!
Regards
Roger
Roger

The main beam tell-tale doesn't come on for either dipped or full beam. I'm going to get a long piece of wire with crocodile bite ends to track everything properly.

Roger, interesting comment - there is a switch on the left side of the drivers' footwell, and I have no idea what it's for! (Just had my 'B two weeks)

Also, my horns don't work, could that be related? According to the wiring diagrams the horns and headlights have a different earth but possibly the same fuse... I wonder where the headlights circuit connects to earth!

Thanks for your help!

- Matt
Matthijs van der Meer

Roger

I just checked the Vicky Brit catalog and the foot headlight dimmer switch is shown for models up through 67. 68 and on have the dimmer included in the turn switch assembly on the steering column. Maybe the change from the foot switch was different on US models?

FWIW

Larry
Larry Hallanger

UK spec cars didn't get the column dip-switch until the 70 model year, padded dash cars (i.e. mainly North America but some other markets at different times) got it for the 68 model year. The headlamp flasher is powered from the same supply as the horns, so if neither of those work it could be common i.e. the brown-to-purple fuse in the fusebox, and this would almost certainly affect the (optional) door-operated courtesy light as well. Totally different supply for the main lighting. The headlight ground to the chassis could be somewhere by the fusebox or behind the dash and is shared with a whole lot of other things like the charging circuit, wipers, heater fan and instrument lighting, but there is a common point that will affect both filaments of both lights at the bullet connectors by the right-hand headlight. But since the tell-tale doesn't light either, then either that is faulty too or there is no 12v supply coming through the main and dip-switches.
Paul Hunt

Paul,Matthijs,

I follow that and was assuming that if Matthijs was posting from the UK, there was a fair chance that his car was UK spec. If that is so, could that "switch on the left side of the drivers' footwell" be the dipswitch and there have been some non-68 spec rewiring done in the past I wonder?

I'll leave electrics guidance to those like you Paul. After all, my very much learner's status is based on studying sites like yours.
Regards
Roger
Roger

Larry,

Sorry, meant to cover your point in prior post. Our cars In Oz (by these years) were being assembled locally from kits imported from the UK. There was an increasing percentage of local content because of government tarif requirements which influenced where things like electrics, glass and trim items came from. For example, my Lucas items seem to be entirely made in OZ items. My car, produced mid 69, also has the earlier, rounded tail lights, where I think the change to the more angular version in the UK was earlier in 69. My understanding of the change point for the foot operated dipswitch for UK spec (and kits exported to OZ) fits with Paul's description.

These variations, intended or for convenience, across the various markets is, I guess, just a part of the mystery of these beautiful little cars.
Regards
Roger
Roger

This thread was discussed between 19/05/2003 and 21/05/2003

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