Relaying dim-dip headlights - Type 44

Huw Powell human747 at
Tue Dec 10 22:50:30 EST 2002

> When I rebuilt my Ur-q I took the opportunity to rewire the headlight loom
> with 2mm cable and install relays. All the relays are mounted inside the car
> alongside of the auxiliary relay plate. This allowed me easy access to the
> dim-dip circuit. I've posted info at

"I tried a number of ways to retain the dim-dip function, one of which
resulted in a rather amusing
self-energising circuit which, unless the correct sequence was followed
would leave the headlights on
when the switch was off - even if the ignition was off too."

hehe, i remember the first iteration of my coupe headlight system had a
few rather unexpected results - things that would stay on under strange
circumstances, things working really weirdly.  A few diodes cleaned that
up, it was mostly due to having relays tied together to be switched by
in different ways by the same signals.  It takes something like 7 volts
to trigger the relay, so "on" was no problem, but they don't turn off
until voltage drops below 5 or so.  So if I had two relay coils in
series "by accident" they might stay on - whichever one was on, that is.

> the new dim-dip stuff is at the bottom of the page.

Cool.  bizarre feature, though.  nice to see it explained, I was really
wondering what that question was all about!

Huw Powell

More information about the quattro mailing list