Apparent Lamp Failure in Dipped beam unit

[Rosebank]

Hello Everyone,
In the three years since I purchased my 75, I have had to replace the dipped beam lamp once, if not twice, each year. However a recent failure has caused me to be suspicious because the lamp filament did not appear to be broken and when re-fitted, there was a glow visible in the lamp. It seems to me that there is a loose connection somewhere in the connector block feeding the lamp or in the earth connector block. The lamp can be made to switch on and off by moving the wiring harness.
Is this a known problem in the 'Community' ??? and is there a permanent solution??
Can any kind person shed any light on the subject???
Regards
Rosebank

[StanUK]

Hello Rosebank

Sorry I cannot help with this problem but it reminded me of a problem on similar lines – the airbag warning light would intermittently appear and had me baffled for a while – until I realised it would come on or off after I had moved the front drivers seat when cleaning the car. There are wires under this seat, and the problem has not reoccurred since I stopped moving it.

[pondweed]

probably the looms starting to chafe on the horizontal members behind the lights... all sorts of strange things start happening. (I lost my sides and headlamp motors at 155,000 miles, with some spectacular shorting when I moved the wiring...)
Check it out, but its probably a bumper off job

[Rosebank]

Thank you, 'StanUK' and 'pondweed' for your comments. I definitely now think I have a problem involving the connector between the wiring harness and the offside headlamp unit. When I moved the connector with the lights switched on, the dipped beam on that side went on and off and some smoke was evident rising from the underside of the connector.
I think I agree that I should remove the bumper and investigate the headlamp connections.
I do not know whether the wiring can be removed from these connectors to allow replacement of the complete connector .
I will try to keep you informed.
Thanks again,
Rosebank

[Rosebank]

Hello 'StanUK' and 'pondweed'
Thank you once again for your interest in my problem!

I removed the front bumper as suggested and found the wiring harness to the headlamp connector to be frayed through the insulating tape and two of the cores of the cables. It had been rubbing against the seam of the horizontal chassis beam as you hinted.
I cut the two damaged cores and inserted crimp connectors and wrapped the complete joint and the adjacent harness branch with new insulating tape. 'Lamp Failure' cured!
I have taken some photographs of the location but I'm not clear how to include them in the message forum.
Thank you very much for your help!!!

Kind Regards
Rosebank

[StanUK]

I see pondweed pointed you in the right direction - glad you got it sorted. These suggestions make us aware of possible future problems and we can check them out before they happen - hopefully :-)