Author Topic: Hig beam indicator bulb wiring  (Read 320 times)

Offline KeithJ

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Hig beam indicator bulb wiring
« on: 19.05. 2016 09:52 »
Hi, I am in need of guidance as my main beam indicator bulb is on for both main and dip beam.  I have fitted an H4 bulb with new reflector and thought all I need do is take a lead from the Main beam terminal on the back of the bulb.  Unfortunately, when I check this out with a meter, voltage is there on both main and dip beam leads even though only the one switched lights.  Hence, the construction of the H4 appears to be different from the original pre-focus bulbs.  The bulb works ok on main and dip and the indicator bulb is wired in after the dip switch.  Do I need a diode or something to make it function correctly>  What am I missing apart from some better grey matter?

Just going to have another look at it.

Thanks
'59 A10RR + Second engine

Offline duTch

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Re: Hig beam indicator bulb wiring
« Reply #1 on: 19.05. 2016 10:57 »

 I guess maybe we need to know if you are 6V or 12V, and +ve or -ve earth, and what switch you are using?

 I'm running a H4/6V/-ve earth, but I don't have an indicator light to tell me either beam is on, although it's often a good idea- saves waving may hand in front to check *eek*

 It has to be something simple, maybe disconnect things until it goes out?
Quote
Hence, the construction of the H4 appears to be different from the original pre-focus bulbs.

 They are different, as no doubt you've discovered, the H4 earth is integrated in the 3 pin insert unit rather than the dodgy BPF setup. *dunno2*

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Online Greybeard

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Re: Hig beam indicator bulb wiring
« Reply #2 on: 19.05. 2016 11:00 »
Is it possible that the bulb is designed so that both filaments are lit on high beam?
Can you check the bulb connections with a Meter or a battery and bulb test rig?

Offline KeithJ

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Re: Hig beam indicator bulb wiring
« Reply #3 on: 19.05. 2016 11:14 »
I thought the "filaments" came on individually but good point and I will check.  With the pre focus, I think the high and low beam filaments are separate electrically but not so sure with the H4. Will look further in to it. 
Thanks
'59 A10RR + Second engine