Does anyone know how the Disco I DRL's work? There is only one bulb. Are DRL's just the high beam at a lower voltage or something?

 

Day Time Running Lights are the low beam's on most cars, the high beams on others.
To turn them on or off in a DI there is a relay that needs to be installed (on) or removed (off)

 

These headlights use an H4 bulb though with filament for low/high. There is only one bulb. Yet if you look at the output of your DRL was turning your lights on (low beam) there is a substantial difference.

That's why I'm trying to work out how DRL's work. Do they just lower the voltage for less output?

 

In the D1 there is a second, smaller bulb inside the head light housing. Mine comes on at the 2nd click, along with running lights. These are sometimes called "city lights" or "sidelight". It is shown on section 86, page 16 of the workshop manual, you can feel the other connector just beside the main bulb. It is a #194 bulb, very small. Nothing nearly as bright as a low beam, and slightly off axis from the head light main bulb. Not sure if this might be related to your question.

 

I think it's a 194...but I could be wrong.

 

I belive u b more awake several time zones away, good point.

 

You could also use a 168 bulb which has one more candlepower than a 194.

/remembers useless facts from bulb specification catalogs

 

That's perfect. Thanks guys. I've never noticed the second bulb so that makes perfect sense.

I just can't stand how ugly the DRLs are so I was hoping to switch that bulb out. Looks like I can do just that now.

 

You could swap it out for a LED bulb for increased brightness...

 

That is my game plan.. Little nicer looking too.