Mark, this is what I used on my recent lighting installation.

On a late model VW Vanagon, there is a "double" relay socket that's nice to
have to set up a few of them. But the ones with a tang or bracket build
into them are nice because you can buzz one into sheetmetal (with the 85
pin grounded to the screw) anywhere you need it, as close to the device as
you want to put it. Then you can use the "old" hot wire to the device as
the trigger wire going to 86.

Another advantage of the design with the built-in mount is that you can use
regular old female spade connectors on the ends of your wires instead of
having to locate and purchase the special female spades with a locking tang
on them that keep them from falling out of the socket that you need with
the kind without the built-in mount.

Jim

On Wed, Aug 21, 2013 at 5:03 PM, mark drillock <mdrillock@cox.net> wrote:

> The horn relay is nothing special, just a generic "bosch style" 4 pin
> relay. Every VW has a couple and many other cars do too. VW refers to
> this one as Type 53 or 24 and stamps that number on the top in big type.
> You can buy the generic version at any flaps, often sold as a fog light
> relay or horn relay, or driving light relay. Commonly used as fuel pump
> relays as well, as in Vanagons. Typically 30 amp, sometimes 20 or 40
> amp, all more than enough for horn use. Sometimes the generics have a
> 5th pin that isn't used for what I did.
>
> The 4 pin relay has pins labelled with numbers and is used thus:
>
> 30  load in
> 87  load out
> 86  relay control input pin
> 85  relay control ground pin
>
> Mark
>
>
>
> Marco wrote:
>
>> Thanks for the tips, Mark.  I have ordered one of those Hella horns from
>> the eBay vendor.
>>
>> Do you have a part # or source for the relay? I couldn't find it in the
>> archives.
>>
>> Thanks,
>> Marco in Seattle
>>
>>