My Headlights Are Soooo Annoying!

[paolow]

hi guys,

well, ive spent a fairly fruitless 2 hours in the garage today and achieved nothing. the problem is that my lefthand dipped beam works ok (albeit with a pretty dim dipped beam) but nothing i do will get the one on the right to work. the wierd thing is both units are perfect on main beam so i dont think its an earthing prob, but it gets stranger. - the power going to the bulb that doesnt light on dipped is 11.89 v - 13 v depending on whether or not the car is running, but a bulb i konw to be good (tested before and after) will not light on it, even with an independant earth. perhaps a clue, but when the bulb is connected, the voltage across it drops to zero. dodgy relay? switch seems ok and this is really annoying me! can anyone shed any light on this problem? it seems strange that a 'live' wire with the correct voltage fails to light the lamp. answers on a postcard?

paolow

[Big Jim]

It's just that you have them wired up wrong.

 

If you look directly at the back of the bulb, the 3 terminals form a 'n' confirgaration. So looking at the back of the bulb /unit, the terminal on the left is your earth (-) the terminal on the right is your main beam feed, and the terminal that is horizontal is your dip beam feed.

 

I'm confident that if you wire them up like this, they will be correct.

[paolow]

cheers jim, ill check what ive done tomorow and report back!

 

paolow

[paolow]

ach, well jim, i went out earlier and checked my wiring with my meter and resoldered a couple of joints that were the wrong way round. but, the o/s dipped light stubbornly refuses to light even though it shows a healthy 12.5 v at the terminal. ive checked the bulb and its fine so im at a total loss. again however, when the bulb is connected the voltage across it drops to zero. im sure this is indicative of something, but what, i dont know.

any ideas?

 

paolow

[Guest TerryBarry]

Sounds like you have a poor joint or connector somewhere in the feed to that light.

When you connect the voltmeter the joint can pass the couple of milliamps required but as soon as you connect the bulb it cannot supply the four amps and just gives up.

HTH

Terry

[Big Jim]

Just run a wire straight to the terminal from another source, if it lights, then it's not the bulb or earth side, and you'll need to check through the wiring back to the switch. It is possible to show 12v, but as soon as you put a load on it, zero, because there is a duff connection (Like Terry says) that's just letting a 'trickle' of electric through, but not enough to do anything.

You could easily try that wire by just linking it to a flasher bulb and earth it.

I'll put money on it that you're using crimp-on connectors! (I won't use them!)

[Guest Takumi]

The sealed headlamp units are really low output - i think around 35/45watt ?? - CIBiE make 7" headlamps (fit the chrome headlamp) that you can change the bulb (H4) to whatever power you want 55/60 >- 90/100 even upto 130/100 watts . the sidelight is a small BC bulb of 5watt.

The units cost about £30+pp each - deffinatley worth over the sealed beam units.

 

From Europa Specialist Spares

 

http://www.europaspares.com

 

 

hope this is useful.

[paolow]

he he,

beat you to it taku! the sealed beam units are already my mates xmas pressie and i treated myself to a pair of proper halogen units from classic car parts. maybe though this is part of the problem? that the current draw is higher so that sealed beam units that did work, now dont? cheers for the ideas jim and terry, ill try applying independent voltage at the switch end to see if i can get it to light, thus eliminating the switch unit from my enquiries and hopefully troubleshoot it from there.

will report back on tuesday when ive had a good old play around.

thanks again guys

 

paolow

 

oh yeah, jim, i was using crimp connectors but the headaches they caused! all my joints are now soldered!