VW Taro (Toyota Hilux Clone) - Spotlight trouble with Dim - Dip

At risk of stating the obvious: whatever it is you have wired the spotlights up in parallel with, the spotlights will do the same as.

I really wish it were that simple. Ignition on or off the only time the Main beam elements light up is when main beam is selected.

However, with the ignition on and side-lights selected, you also get dim-dip on the dipped beam elements. However, some 'stray' volts arrive from somewhere and trip the relay so the spotlights come on.

It is definitely associated with dim dip, as when you go to dipped beam instead of sidelights with dim-dip, the spots go out.

It is the workings of the Dim-dip that have me foxed....

Mark

Whatever. If you have your spotlights in parallel with the main beam elements, they will do whatever the main beams do. If they're not doing the same, it's because they're not in parallel with them. Dress me up in ribbons and call me Aunt Daisy if it's not true.

Maybe the main beam filament is partly lit, i.e. with a low voltage, on dim-dip. This lower voltage is then still enough to trip your spot light relay. This would give the behavior you have described. If this is the case you need a way of getting the relay to only trip when it sees full battery voltage, I dont know how.

Steve

Thats what I thought at first, although the Main Beam filament does not appear to glow, visually, only the dipped beam filament comes on for the dim-dipped beam.

I agree with your solution being one option, but also agree with your second statement!

May not be enough volts to make it glow. Bear in mind power dissipation of a bulb is proportional to the voltage across it squared, in other words power dissipation at say three volts would be not 3/12th but 9/144th of full-power dissipation, i.e. bugger all. Any idea what voltage is being dropped across the main beam when the dim-dip is on? Can you bang a mutleymeter across it and get back to us?

Sorry for the slightly arsey "it'll do whatever the main beam is doing" response earlier, I hadn't appreciated that relays were involved, I thought you were just putting the spots in parallel with the main beam. :-)

Doesn't dim dip work by connecting the filaments in series? to do this it must suspend the earth connection, this means that the main beam filament will be floating at 6v? You need to find somewhere else like the feed to the dashboard hi beam indicator OR connect the relay directly across the main beam filament so the earth of the relay coil is suspended as well?

Maybe a Zener diode in series with the relay coil, which will only start carrying current when the voltage is above the Zener diode voltage rating. You'd need to look hard at the current rating you required (i.e. greater than the current the relay coil carries), and the power rating (= relay coil current in Amps x voltage rating of the Zener diode), and you might need some heatsinking.

richard ( snipped-for-privacy@tiscali.co.uk) gurgled happily, sounding much like they were saying :

No.

It uses a pair of relays to pass the side feed through a big resister to the dip filament. Earthing isn't touched.

No worries. Now fetch your ribbons Aunt Daisy! ;-)

Mark

You trying to turn me on or what? Follow-ups set to uk.people.crossdressing. ;-)

Fords of the 1990's definitely put the dip filaments in series.

I remember having a blown dip bulb which put out dim-dip on both sides. They had to be in series for this to happen.

I've just dug out my old Haynes for Escorts of that era, and on the wiring diagram there is no resistor shown. Also the common from the two filaments is switched through one of the dim-dip relays.

I would imagine that different manufacturers use other techniques however.

Chris

Are you sure the headlights are switched positive? A lot of japanese vehicles used to use switched earths for lighting.

I know that when I added spotlights to my bro's old shogun, it gave some funny symptoms until I figured out just what was going on. I can't quite remember how I got around the problem. I think it involved the addition of an extra relay, but it was a few years ago, and the details have been forgotten.

Err nope. Quite a few vehicles just connected both filaments in series.

Why not wire in an extra switch in the cab as an enabler? i.e. you keep the feed you already have and as long as the cab switch for the foglights is on they will come on but they can be over-ridden to be off when the car is on dipped beam that way. All you would need to do is wire the dim/dip feed from the headlamps through a small switch and that then feeds the relay coil.

Chris

Surely if you're getting into added switches then you might as well wire the fogs direct to the switched +12V.