Auto-electrical help?

[MoreWellie]

Also, make sure the indicator light bulb glass is clear, and not blackened with sputtered tungsten.

I would also check the blue filter/bulb cover by shining a torch through the hole with the bulb out

 

[Myles1970]

Earth is good, less than 1ohm. Also, thinking about it all of the other warning lights are bright, and I'm sure the earth is common across the combination meter.

At full beam, there is 6volts dropped across this bulb, 0v at the earth as one would expect.

Removing the indicator bulb makes no difference to the intensity of the headlamp, which suggests to me that the dips are still earthed through the switch...

 

[Myles1970]

I would also check the blue filter/bulb cover by shining a torch through the hole with the bulb out

Yep, tried that, good with a torch

 

[Myles1970]

I've also realised that contrary to how it appears on the wiring diagram, the lights switch and the main beam/dipped beam selector are not one unit; hi/lo is selected with the indicator stalk, whereas on/off is done by twisting a switch on the dash.....
I think that since the other lamps on the display are 12volt and this one is 6, that a 6v led could be the way forward. Could be that the correct bulb was swapped oit

 

[MoreWellie]

Removing the indicator bulb makes no difference to the intensity of the headlamp

wouldn't expect it to. The high beam is getting 12v on one side and earth on the other
the 12v is then feeding through the pair of dipped beams and to the high beam indicator lamp

which suggests to me that the dips are still earthed through the switch..

try removing the headlight bulb cables and the indicator bulb and then see whether there is any continuity between the two connections for the indicator bulb

Getting 6v is weird as the two dipped beam filaments will have way lower resistance than the little indicator bulb so I would have guessed that you should measure close to 12 and certainly between 11 and twelve

I take it with the indicator bulb out you do get 12v across the two connections for it

 

[Myles1970]

wouldn't expect it to. The high beam is getting 12v on one side and earth on the other
the 12v is then feeding through the pair of dipped beams and to the high beam indicator lamp

see, this bit confuses me (not difficult, I know). As I see it, on dips, the high beam warning lamp is short-circuited, so it shouldn't light(?)

try removing the headlight bulb cables and the indicator bulb and then see whether there is any continuity between the two connections for the indicator bulb

I will try this

Getting 6v is weird as the two dipped beam filaments will have way lower resistance than the little indicator bulb so I would have guessed that you should measure close to 12 and certainly between 11 and twelve

I take it with the indicator bulb out you do get 12v across the two connections for it

No, the 6v is with the bulb out

 

[MoreWellie]

As I see it, on dips, the high beam warning lamp is short-circuited, so it shouldn't light(?)

Correct, but when on high beam the 12v is fed through the two dip beam filaments to the high beam indicator lamp

 

[MoreWellie]

No, the 6v is with the bulb out

This doesn't make sense, let me ask some basic questions
1. The battery is a 12v one?
2. what volts reading do you get measuring from 9G to the positive terminal on the battery
3. what volts reading do you get measuring from 10F to the negative terminal on the battery
4. Do the dipped and high beams actually work properly (look at the pattern)
5. If the answer to 4 is no then have you rewired the headlight connectors and got 1 2 and 3 mixed up as putting volts on 2 and earth on 1 (or vice versa) would give you 6v on 3

 

[Myles1970]

1. Yes

2 & 3...... To follow

4. I thought they did

5. Could be on to a winner here...

 

[Myles1970]

And the winner is: @MoreWellie ,
Genious! This has been doing my head in for the past few days. When you suggested I got some of the wires at the headlamp swapped around it occurred to me that if you turn the bulb on its side both filaments would be activated and the 6v would appear at the common terminal

Thanks again mate!

 

[colnerov]

It's good that you've got it sorted. However I think it's a strange way of doing it, I've always done it with the telltale in parallel with the main filaments.

Colin

 

[carbon]

Some older Mitsubishi’s are also wired the same way.

 

[Keithmac]

Japanese love using switched earth systems.

Nice to see you sorted it out.

 

[voipio]

Well done!! :-)