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Vintage Cars/Austin healey BT7

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DEAR JO MY AUSTIN HEALEY UP GRADE REAR INDICATORS HAVING TAKEN WIRE FROM BACK LIGHT INDICICATOR WIRE TO NEW INDICIATOR AS AN EXPERT YOU WILL KNOW REAR LIGHT HAS 3 FUNCTIONS BRAKE,BACK LIGHT AND INDICATOR HAS ONLY 2 WIRES AND AN EARTH,IF I TAKE THE INDICITOR WIRE I AM ALSO REMOVING BRAKE LIGHT CAN YOU HELP PLEASE

Answer
Before the answer... If you're going for the new LCD lamps, be careful: they need negative ground, and you'll need a new flasher unit for the lower amperage as well. (Write again if you need to know whether you can change your car to negative ground.)

Anyway, the question: the bulb has 2 brass connector nibs on the end (one goes to each filament) and is grounded through the lamp socket and the screws that connect it to the body. The brake and indicator functions share 1 filament (25W in standard bulb format). The thinner filament (5 W) is the parking light. The brake lamps are powered from a relay box located way up front near where the indicator-switch wires come out of the steering box. When you have flasher and brake on together, the relay switches the brake lamp supply to the appropriate (left-right) flasher circuit. The other brake light stays lit. When braking with the flashers off, the relay sends power to both sides together, not through the flasher.

Hope that explains it!

PS: hint...

Thanks for the vote of confidence! If you're (re)installing ordinary incandescent (25/5 W) lamps, a hint to make them brighter. Double fold and cut a small circle of aluminum foil, shiny side out, and cut a hole in the middle. Push the bulb base through the hole. Install the bulb in the socket (make sure not to get foil into the socket) and press the foil down to surround the bulb, up to the groove in the rubber. Install the lens. The foil reflector makes the lamp quite a lot brighter.

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Jo Jesty

Expertise

Most detailed about Austin Healeys but also MGs (A,B,C), old Minis, old Volvos: they share SU carbs, Lucas (Prince of Darkness!) ignition, Girling brakes & shocks. Some things shared with TRs too, but I don't know so much about them. Can advise the semi-neophyte on the basics of keeping things running, especially tuning ignition and carbs; but no rebuilding engines or transmissions; no frame or bodywork. General date range: late 50s to 70s (not so good about cars with emission controls, electronics). No valuation experience at all.

Experience

Middling: I am not an auto mechanic. (Should we stop right here?) Grew up In England and a workshop. I have had a 3-carb 60/61 Healey for ca. 8 years, largely looked after myself. New fuel system and carbs, resuscitated ignition, brakes (discs and drum). Great driver's car. Major jobs done by others: king pins, front frame cancer excision; caliper rebuild; etc. Organizations.: Austin Healey Sports & Touring Car Club (PA) Publications: > 70, irrelevant Education/Credentials: PhD, irrelevant Awards and Honors: irrelevant Languages: Je peux essayer francais...


Education/Credentials
Re. cars, none--see experience.

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