Indicator light in speedo problem

[bcmc33]

I have just noticed this week that the indicator light does not flash when the indicators are working. When the indicator arm is moved (in both directions) the light flashes once only and then dies.
The last time I drove the car in the dark - probably April/May the light was working perfectly.

I never really look at the light as I have a buzzer to let me know that the indicators are working - but I would be interested to hear what the problem is before I go out and buy a new flasher unit.

[leifanten]

Could it be as simple as a burned out bulb? Otherwise I would put my chips on earthing/connectivity.

Leif

[bcmc33]

Leif,

I hope you're not a gambler. Bulb and earthing are both good.

[paddy]

I think it's the flasher unit, and you need either a replacement or just to clean out the cobwebs and brighten the contacts.

The flasher unit drives the indicator lamp, and the wiring from the flasher to the lamp and the lamp itself are obviously OK, so the entire circuit is OK apart from the flasher unit. I can't really see how it can be anything else. (Famous last words ...)

Paddy

[bcmc33]

I'm still at a loss on this one.

Bought a new flasher unit and the result is the same.

Has anyone any ideas??

[pamitchell]

Indicator arm contacts are worn, loose?

[john.p.clegg]

Brian

Are your indicators working,I think it's the current flow through the indicators/flasher that powers the on/off?

John

[bcmc33]

John,

The indicators work perfectly.

[69S4]

I never really look at the light as I have a buzzer to let me know that the indicators are working

Are you using the std thermal flasher unit and if so how have you got the buzzer attached to it? What happens if you unplug the buzzer?

Stuart

[Frank Howard]

Brian,

I'd disconnect the buzzer and then see what happens.

[bcmc33]

Disconnecting the buzzer was my first thought and action - but it makes no difference.

To eliminate any possible car interference I did a bench test with both flasher units and the dash indicator bulb only flashed once while the main bulb flashed as normal.

The mystery continues.

[alexblack13]

Try a test wire from a good proven earth point to the speedo. Just hold it on to test... Or, use a meter for continuity test. No earth means no indicator light. I think!

Alex B....

[bcmc33]

The car and bench earth connections are perfect, Alex.

[paddy]

Brian,

First of all, sorry if my advice led you to buy a new flasher that turned out not to solve the problem.

If I understand correctly, you're saying that you have replicated the entire circuit on the bench, away from the car, and it exhibits the problem with either flasher unit.

In that case, is there any part of the circuit that is not new? Could it be the indicator lamp itself? I've no idea how that might be the problem, but what's left? Is the supply voltage OK?

It's quite mysterious.

Paddy

[bcmc33]

Paddy,

Most frustrating.

I've tried creating a new circuit in the boot space with a supply direct from the battery and a link to the rear indicator. I've tried four different bulbs including an LED for the panel light and they only flash once even though the three side indicators continue to work perfectly.

In sheer desparation I shall attempt to persuade a friend to test both the flasher units in his MGB tomorrow.