Electrical teaser

luxy, Mar 12, 8:35am
I have a mid 50s english car.The rh headlight has blowin the low beam twice recently. i have now noticed that with the low beam blown, when I put the lights on( low beam)!I have no dash lights until I hit the dip switch onto high, then I have both lights going and the dash lights! Where should I look first to solve the fault
monaro17, Mar 12, 8:40am
Perhaps a broken filament has fallen down and is now short circuiting and losing grounding. And when power is put through the other filament it completes the circuit again and grounds it. (hope that makes sense!)
ola_bitchola1, Mar 12, 8:41am
possibly look for a grounding issue hell with a 50s English car im surprised that is the only electrical fault
pdc1, Mar 12, 9:55am
He wasn't called the Prince of Darkness for no reason.
sr2, Mar 12, 10:48am
LOL; +1,000,000%! Having owned (and enjoyed) numerous post war English cars I couldn't agree more.
socram, Mar 13, 6:56am
LOL.However, at least you can identify just about any wire in a British car from the colour(s) without needing a wiring diagram and a multi meter!

I have totally rewired/redesigned my 1950's Brit car from scratch (using the BS/Lucas colour codes and separate fuses for everything) and with no computers at all, I'm willing to bet that it won't ever be faced with the "Oh! I'm sorry sir, they stopped doing those circuit boards/chips/ECUs/lambda sensors etc, 10 years ago."

Let us know how you get on OP.Always good to hear a result.#2 & #3 are probably correct (they know more than I do) but I'd also check the dashboard earth(s), as the dash lights are normally on the same circuit as the side lights.You haven't said whether or not the side lights are on when the dash lights are off!Wooden dash or metal dash!
intrade, Mar 13, 7:48pm
dont forget english cars run + to ground of that age. and minus to divises
bashfulbro, Mar 13, 8:02pm
I had this exact this problem once, you are quite likely right.
intrade, Mar 13, 9:02pm
or simply the way the elctrics work is that both lights are on on high beam, would not surprise me either like power from high beam looped to low beam bulb back also.
steptoe72, Mar 13, 9:59pm
Thats a easy fix.to make it - earth.