My hell super tones have a relay that came with them. I would probably need to replace the OEM one for the Hella one, but I am not sure. Better to be safe than sorry. THE FSM says the relay is located "on the left side dash side panel" Is that near the hood release handle?

Also has anybody else hooked these up? Did you use the Hella relay or the OEM one.

I just got some Hella twin power horns from Griot's, and they came with a relay too. Did you ever figure out the answer?

Location of horn relay on a 1970 car, just above hood release.

You know all I did was hook up the wires from the existing horns to these and run a ground from the horns to the chassis.

Works beautifully

Y'know, that's what I ended up doing today too just to see if it would work/blow a fuse, etc..... And they are pretty darn loud. I wasn't expecting them to be a single tone though. Anyway, I think the idea behind the relay and direct battery connection is to get more juice to the horns than the stock wiring may be able to handle. So I might still try it that way to see if they get even louder (I don't have a decibel meter though).... but I think that my goal of having loud enough horns to say "Hey, you in the SUV, don't change lanes onto my car!!" has been achieved

Y'know, that's what I ended up doing today too just to see if it would work/blow a fuse, etc..... And they are pretty darn loud. I wasn't expecting them to be a single tone though. Anyway, I think the idea behind the relay and direct battery connection is to get more juice to the horns than the stock wiring may be able to handle. So I might still try it that way to see if they get even louder (I don't have a decibel meter though).... but I think that my goal of having loud enough horns to say "Hey, you in the SUV, don't change lanes onto my car!!" has been achieved

You will want a fuse in-line with the power feed from the battery or after the relay to the horns. Regardless, put a fuse in the circuit somewhere. I was going to buy the Hella Supertones but after doing a bit of reseach I opted for the FIAMM low tone and high tone horns. They are not as harsh as the Supertones and have both a low and high tone horn.

FIAMM's are super nice.

I found the supertones for much less, no doubt the FIAMMS are a super quality unit.

You will want a fuse in-line with the power feed from the battery or after the relay to the horns. Regardless, put a fuse in the circuit somewhere. I was going to buy the Hella Supertones but after doing a bit of reseach I opted for the FIAMM low tone and high tone horns. They are not as harsh as the Supertones and have both a low and high tone horn.

Yes, I still have the stock Horn fuse in place (which is 10A, but the horns are 5.5A each) and if/when I try the Hella relay I will use a 20A inline fuse between the relay and batter per the intruction sheet. Thanks!