15 replies to this topic

[Minigman]

A bit of a weird one this.

I replaced the lamps on my centre mk3 speedo for LEDs.

They’re very good!

Since then the green indicator lamp only flashes when turning right.

All external indicators are working and the relay is clicking away fine.

I can’t see any obvious loose cables.

I screwed the old original style lamp back in and it no longer works either.

Any ideas where to start looking?

[KTS]

LH turn signal comes into the centre binnacle through the Green/Red connection at the multiplug connector - check you've got a good connection across the connector, and from the connector to the warning bulb

[Minigman]

LH turn signal comes into the centre binnacle through the Green/Red connection at the multiplug connector - check you've got a good connection across the connector, and from the connector to the warning bulb

Already traced and checked. Can’t see anything wrong. Will have to check again in guess. I think it’s wires straight to the multi plug. There’s no connector between the two is there?

[KTS]

both LH and RH wires normally run straight from the multiplug to the warning lamp.  problem at the lamp fitting maybe ?

[unburntfuelinthemorning]

The single indicator bulb in the centre speedo has current flowing through it in opposite directions depending on the indicator switch setting.

 

An LED is a diode which only allows current to flow in one direction so will not work in the way a conventional bulb does.

[Minigman]

The single indicator bulb in the centre speedo has current flowing through it in opposite directions depending on the indicator switch setting.

An LED is a diode which only allows current to flow in one direction so will not work in the way a conventional bulb does.

That does make a lot of sense.

I’ll try another conventional lamp in it. Maybe the one I swapped it out for I broke as it didn’t work when I put it back in.

Thanks

[Ethel]

As above. The dash bulb is wired between both sides so it uses the non flashing side as an earth. It mustn't earth on the Speedo casing like the the other lights. Excluding the ignition light which is also insulated so it lights when there's sufficient difference in voltage between the battery and alternator.

[viz139]

If you get the original lamp working again and than want to refit the led you can do it using a bridge rectifier. Cut the two wires and join them to the AC input of a rectifier and than join the LED to the DC output + and -. 

[KTS]

you can sidestep this particular issue if you split the L&R indicator feeds to the single lamp and make use of the two orange lenses on the speedo face.  does mean the oil pressure warning lamp will need to move to where the indicator lamp was though so it'll be a green lamp instead of orange..

[unburntfuelinthemorning]

A lot of older cars such as Land Rover and Triumph used to use green for the low oil pressure warning lamp.

[KTS]

A lot of older cars such as Land Rover and Triumph used to use green for the low oil pressure warning lamp.

 

presumably because they were using the same smiths speedo and the two orange ones were being used for the indicators 

[unburntfuelinthemorning]

No they used quite different Smiths speedos and sometimes had separate warning light clusters.

[GraemeC]

you can sidestep this particular issue if you split the L&R indicator feeds to the single lamp and make use of the two orange lenses on the speedo face.  does mean the oil pressure warning lamp will need to move to where the indicator lamp was though so it'll be a green lamp instead of orange..

With a scrap speedo and some care, you can swap the jewel lenses so the individual left & right indicators are both green and the oil pressure (in the old indicator location) is still orange.

[Minigman]

I’ve chucked an old type lamp back in now and all good.

Also the ignition light stayed on too with the LED so that’s come back out.

Regarding the LED lamps. It’s really only the two back ground ones that need a boost, the warning lights are fine as standard lamps.

[Ethel]

The ignition light tells you a lot more with a filament bulb. If it gets brighter with revs the alternator is pumping out higher voltage than the battery. The other way round suggests the battery is draining.