headlights turning themselves on and off

[docgibbons]

I had a bit of a problem last night having set off in sunshine on a visit to a chum and come back home in semi darkness. all of sudden I couldn't see much ahead, and realised the headlights had turned themselves off. Also, the full beam red light was glowing. Then, the full beam light turned itself off, and the headlights came back on. This sequence continued right through the last 30-40 mins of my journey, and was a bit hairy at times! The front and rear sidelights were not affected.
Anyone any ideas? Something loose somewhere? Need to get it sorted with the days getting shorter.

[bmcecosse]

What age is the car? Are you sure it wasn't loss of dynamo charge that is the problem - cutting out and then on again? On later cars the red light is the dynamo 'no charge' warning, and the full beam warning is a blue light. I would start by tightening the fan belt (and fit a NEW one if you find it very loose..) and the dynamo connections.

[docgibbons]

hi there. it's a 1958 saloon, 948cc. I've checked the fan belt and it seems tight enough, and the dynamo connections look ok although not entirely sure how to check these out fully. there are three warning lights, two lower down and side by side, the left one green (oil) and the right one red (ignition). The top one is "high beam" and this is the one glowing red when the lights go off. I've tried the lights this morning, while parked, and the lights seem to be ok, with the high beam indicator light working (and glowing red, not blue). Now I think about it, while I was having the lights issue last night the dip switch was not working. ie, when the high beam (red) light was off - which meant the lights were working - I tried the dip a couple of times and nothing happened. this morning, though, it all seems ok. I wondered whether it might be road vibration shaking something loose, but I hadn't considered the fan belt/dynamo possibility.

[bmcecosse]

Well - that's why I asked the age of the car...... So 'main beam' warning is indeed red on that age of car. Hmm - I would certainly check all the connections down at the dip switch. Give them a good tug...

[docgibbons]

the old boy is going into the garage on monday, for new front shock absorbers, and will get everything checked out at the the same time, including those dipstick connections.

[katy]

dipstick connections

Hmmm, vvery interesting.........

[bmcecosse]

New front dampers??? Have you tried just filling them with oil........???

[docgibbons]

dipstick? no that's me. I meant dip switch!

[docgibbons]

got it back from the garage today, headlights now working ok.
apparently the earths to both headlights were faulty, and needed cleaning and re-wiring, and this appears to have solved it.

[bmcecosse]

Strange that they would both fail at the same time.......

[docgibbons]

I thought that also, especially as they turned themselves off at the same time, with no gap in between. so not totally convinced. we'll get a chance to find out soon, though, with the days getting shorter.

[docgibbons]

i'll ask the mechanic to be more specific and post his explanation.

[bmcecosse]

It's not important - as long as the problem has been resolved.......but 'mechanics' feeding back bullsh!t really really annoys me....

[docgibbons]

me too, if it really is bullshit. I will definitely get the mechanic who worked on the car to explain, and then post his comments. the steward at my golf club is an old car enthusiast (he owns a triumph spitfire) and he was certainly sceptical about the garage's "fix".

[bmcecosse]

Unless the wires go to a common 'earth' point of course.......