Joined: Aug 2017 Posts: 1,257 Threads: 219
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Location: North Herts
Some time ago I fitted good quality LED dipping headlamp bulbs to the Ruby. All seemed fine, with lots of lovely bright light.
Last evening I was out and about in the car and used the headlights for the first time.
I have found that when the brake lights come on the headlights go out. Similarly, when I use the flashing indicators the headlights flash off and on.
Any suggestions of the cause please?
Joined: Aug 2017 Posts: 529 Threads: 17
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Location: Hampshire UK
Hi
As lights earth to the bodywork, I suggest you first check the earth connection between the body and the chassis/battery return
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I agree with John, these new LED lamps are very susceptible to an indifferent earth....
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Location: Beautiful Northumberland
Car type: 1933 RP Saloon (aka Mildred)
That was always a classic 70s car problem. My Cortinas used to do that. Indicators on and brake lights used to flash. Opened up and were like a sauna from poor sealing and of course a rusted poor earth so the lights earthed through the next best/available route, another bulb. 5 mins with wet and dry and all was fixed.
Enjoy yourself, it's later than you think!
Joined: May 2018 Posts: 2,802 Threads: 533
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Location: Peak District, Derbyshire
Car type: 1929 Chummy, 1930 Chummy, 1930 Ulster Replica, 1934 Ruby
16-05-2023, 11:15 AM
(This post was last modified: 16-05-2023, 11:23 AM by Tony Griffiths.)
LEDs draw so little current that good earth is (as others comment) absolutely essential. I'd run separate wires from each headlamp back to the battery's negative terminal. Decades ago, to brighten the ordinary bulbs, I used to solder the wires onto the bulbs and run an earth return back to the battery. The difference in light output was immediately clear and a photographic light meter (remember those?) showed a reading about 20% higher.
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Location: Cheshire
The LED indicators I have seem to need about 5 volts to work properly - or they just fizz rather than flash. It can be worth looking at what voltage is actually being supplied to the LEDS under different operating conditions - with various lights on, battery only, or with the engine running - to see how well the wiring system is coping. (In the old days, remember how the the side lights used to dim when the headlights were switched on?)
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Location: North Herts
Thanks chaps. I shall follow the advice and report back in due course.
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Location: Deepest Frogland 30960
Car type: 1933 RP Standard Saloon
In the first instance I would run a separate earth lead from each headlamp bulb holder to a suitable and reliable earth on either the crankcase or even directly back to the battery. Whilst they don't need much current to operate, LED bulbs are particularly earth sensitive.
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Location: Dunchurch, Warwickshire
An excellent earthing point which I use on all my cars is a P-clip made of brass soldered to the oil pressure button/gauge pipe behind the dashboard. Fit a 2BA bolt through the stem of the P and take all the earth return wires (as noted above) back to that.
Joined: Aug 2017 Posts: 1,257 Threads: 219
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Location: North Herts
This morning I disconnected the earth wires from both the headlamp bulb holders (the other ends of the wire are soldered to the body of the lamp) and ran wires from both directly back to the battery.
However, the brake/indicator on/off issue is still there. Any suggestions on where to go next? Do I have to try direct earthing all four indicators and the brake lights? I should say there is no issue when using normal incandescent headlamp bulbs.
