Aftermarket Horn Install

[Killer Frogs]

I have a Hella horn to install. It has two terminals on each horn that are not labeled as positive or negative. It has two instructions depending on if the output from the horn button is positive or negative. Any guidance would be appreciated.

 

[DirtDonk]

If this is for your '73, and it's a "normal" '73 (normal for a Bronco anyway ;D ) then the line from the horn button "should be" positive 12v.
But no matter how it's wired, you can simply use the old Blue w/yellow wire at the original horn as your switched power to the new Hella relay's #86 terminal.

In other words, if it's a normal '73, use Diagram 2B in the instructions and get a new power wire from the battery to #30 on the relay. Ground #85 and run a new wire from #87 to the horns.

Now, for which one of the terminals on the new horns is positive and which one is negative, if they don't mark it, then it shouldn't matter.
But I always thought it did matter on a horn? Are there any markings or letters at all at either of the terminals on the horns?

Paul