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OT - VW Taro - Spotlight and Dim dip problem.

Not a landrover, but seeing as you are such a knowledgeable bunch, I am hoping someone here can help me out of an embarrassing problem. I agreed to wire up some spotlights on my brothers VW Taro (Toyota Clone). Plan was for them to be linked to main beam, in that they would be on with main beam, but otherwise off.

I have wired several sets of lights like this other cars, and had no problems. I thought I was fine this time too, as everything seemed to work as expected. However when he turned the ignition on, the spotlights also come on with the dim-dip headlights. they go off again with the dipped beam, and then on again with the main beam.

This seems to be something to do with the dim-dip function, but I have no idea how this works, or what to do to fix the problem.

Currently I have a relay, with fused live to lights, and switched live spliced onto one of the main beam feeds.

What does dim dip do to this feed? How can I stop it? is there somewhere else (convenient) that I could pick up the switched feed from?

I have suggested he should simply sell it and buy a 110, but some people just can't take goog advice. Thanks in advance

Mark

Reply to
mike whiskey
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I think dim dip works by applying 10 volts (ish) to the main beam lamps ( or filament in a 'normal' bulb). This would be enough to bring in the relay and give the results you describe. You may be able to get a feed from the main beam relay that is already there?

Richard

Reply to
Richard

On or around Sat, 02 Dec 2006 23:05:43 GMT, "Richard" enlightened us thusly:

dim dip systems vary. some just supply the dip beam filaments via a fat resistor - others are more clever; I had fun with the LDV convoy one which uses 3 relays to change the dip beams from being wired in parallel to being wired in series.

On a cunning one such as that nothing's certain - you need a wiring diagram for the circuit. Mind - if you correctly identify a main beam supply, that shouldn't be involved in the dim dip. Dim dip, is, as it says, dipped heads, so not main beam by definition.

Reply to
Austin Shackles

The dim dip systems that do not use a big resistor to drop the voltage (such as Landrovers) work by rapidly pulsing the 12V on and off. The filaments average these 12V pulses so giving a dimmer output.

I suspect what is happening is that the relay that you put in to run the spotlights is sensitive enough to be energised by the pulses. What you need to do is find the feed to the headlights that is only there on main beam. This may go to the dim dip unit, but it may not. If the car has a relay to control main beam, use the feed that energises that. You really need the wiring diagram to find out how it is wired up.

Regards Jeff

Reply to
Jeff

On or around Sun, 3 Dec 2006 10:25:18 -0000, "Jeff" enlightened us thusly:

I've not seen on like that - they might, but I can't see that improving bulb life.

I have, though, seen one that changes the dipped headlamp filaments from parallel to series wired, which, once I'd sussed what it was doing, I thought was rather clever.

Reply to
Austin Shackles

The dim-dip boxes that look like a flasher unit contain an oscillator and a power transistor to pulse the headlights. It is a much simpler solution, wiring wise, than trying to series/parallel the headlights.

The RR that I repaired had an NE555 timer as the oscillator and a power MOSFET Transistor to do the switching. Since the transistor is just switching on and off there is not much heat generated, it is a similar principal to a room light dimmer switch but for dc rather than ac.

Regards Jeff

Reply to
Jeff

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