[T3] Horn Issue

[Jim Adney]

Thanks for the correction, Sean. I've little direct experience with '67 and 
earlier. Seems odd to me that VW would have provided unswitched power to 
the horn, but they may have been worried about too much current thru the 
ignition switch. Water cooled VWs introduced the so-called X-relay (X for 
extra) to switch a lot of those loads, so the ignition switch only had to carry 
the relay coil current.

You correctly added the interior light to things that need full time power. I 
hadn't thought of that.

I'll have to check some of my later cars to see if the brake lights work with 
the key OFF. If they do, that comes as a complete surprise to me.

Jim

On 31 Jan 2026 at 13:53, Sean Bartnik wrote:

> I hate to disagree with the great Jim Adney, but in fact on early models the horn was wired to be powered with the key off.
> 
> You can see this reflected in the ´65 wiring diagram (and perhaps others, not sure what year it changed) where the power to the horn is routed through the same fuse that powers the dome light and the clock.
> 
> This did change at some point on later models.
> 
> On the early cars there is another weird quirk which is that the brake lights are not powered unless the key is on. On later cars, this was changed so that the brake lights work whether the key is on or off. I think this change was in place by ´68 but not sure exactly what year it happened.
> 
> -Sean
> 
> > On Jan 31, 2026, at 12:55, Jim Adney <jadney at vwtype3.org> wrote:
> > 
> > On 30 Jan 2026 at 18:42, Jesse Hernandez wrote:
> > 
> >> I had a similar horn issue with my ~67 fastback draining the battery. 
> >> The mechanic rewired the horn to the ignition switch so I can only honk
> >> when the ignition is on.  That was in lieu of disassembling the steering
> >> column.  No battery drain, but in hindsight perhaps not the best idea.
> > 
> > I agree that bypassing the problem was a poor solution, but your message 
> > highlighted the elephant in the room that none of us had noticed.
> > 
> > The horn should NOT be powered when the key is OFF.
> > 
> > I have to admit that  I'm not really famailiar with our wiring before 1968, but 
> > I'm pretty sure that VW never would have left power to the horn with the key 
> > OFF. There aren't many things that might need power with the key OFF: 
> > parking lights (maybe), side marker lights (maybe), radio (maybe). The only 
> > one that I can think of that really needs full time power is the clock. The horn 
> > would be a definite NO in my mind.
> > 
> > So your mechanic did at least half of the job correctly, by moving the horn to 
> > a switched fuse.
> > 
> > -- 
> > *******************************
> > Jim Adney, jadney at vwtype3.org
> > Madison, Wisconsin, USA
> > *******************************
> > 
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-- 
*******************************
Jim Adney, jadney at vwtype3.org
Madison, Wisconsin, USA
*******************************