[T3] Lights

Jim Adney jadney at vwtype3.org
Sat Nov 4 14:43:34 PDT 2017

On 4 Nov 2017 at 17:21, Dave Hall wrote:

> Thanks, Jim. I wondered how the bulb failure system worked. Further
> research is indicated.

Yeah, this was always a mystery to me, part of which was that there is a 
second relay in our TS flashers that I couldn't explain. it didn't occur to me 
until a few years later, when I was looking at SCR phase control switches 
that I saw that they make special versions "for tungsten loads." I didn't 
understand what that meant, until I remembered that light bulbs have huge 
inrush currents, so the SCRs have to be rated for that. And that inrush 
current would trigger the 2nd relay in our flashers.

I rebuilt a TS relay for someone on this list a few years ago, and I could 
never get it to work right on the bench, because I was just loading it with a 
resistor. I never heard how it worked on the car. If that person is reading this, 
let me know how that worked. If there was/is a problem, I think I can improve 
on it now.   

If it worked, that would be good news, too.

Jim Adney, jadney at vwtype3.org
Madison, Wisconsin, USA

More information about the type3-vwtype3.org mailing list