Cadillac Horn Mod

[sly]

The relay should handle 20-30A. The circuit I think is fused at 10A. From what I remember, I think my 88 had a draw of about 4-5A total.
The universal relays should be rated for 30A. You can run a fused wire from the battery using one of those inline fuse holders and install a 15A fuse to a relay and then trigger that relay with the stock horn button.

you can read up on this stuff here: https://www.the12volt.com/relays/spd...ive-relays.asp
the 12 volt .com is a good source for beginners and experts alike.

Check the ads at the bottom of the page and buy a pack of relays with the wire harness and that will make it much easier to swap in.

[TheEnglishChap]

Sly, to make sure I comprehend you...
From +ve battery terminal use an inline fuse to the relay, then keep the original wiring from the relay to the horns.
What gauge wire should I use for the in-line fuse?
This is the in-line fuse I am looking at getting today...
https://www.napaonline.com/en/p/BK_7...pressionRank=1
As for the relay... I will speak with my NAPA store and see what they have.

[sly]

If you go a new relay route, just use the horn button input to the original relay and run your own to the new stuff.
Pretty much yes, that fuse holder. Use that same gauge wire or 16 gauge and you'll be fine. Run the fuse at the battery (starter solenoid - battery side), then run wire to the relay common, then same wire from the normally open on the relay to the horns. Then just run some wire to ground the other side of the coil on the relay that the horn button wire will go to.

Quick paint diagram:

[TheEnglishChap]

I would like to thank everyone in this thread for your support.
Installed the ACDF horns - sound epic!
Here is where they are located:
One in each of the original location, and the other two close by behind the headlights.
No additional drilling needed (fortunately!).
Had to cut off part of the horn mounting bracket to fit, but other than that, no major work needed.
Used an inline fuse holder, with a 30A in it.
Original relay kept.
Mounted each of the four ground wires to the body. Positives linked together using the original connector from both sides.
One of the easiest things done to the car.
Sounds a peach!

[Lutrova]

Good to hear it was such an easy install. Could you post a picture of the holes you used to mount through?

[sly]

I would reduce the fuse to 15 or 20 as the 30 will not protect the wires. The wires are too thin and will fuse first before the fuse would blow.

[TheEnglishChap]

I would reduce the fuse to 15 or 20 as the 30 will not protect the wires. The wires are too thin and will fuse first before the fuse would blow.

I used a 20 and it blew that!

[TheEnglishChap]

Good to hear it was such an easy install. Could you post a picture of the holes you used to mount through?

I will have to get photos when it is a little cooler. Shocked to say it is in the low 90's out here in WA today... where it was miserable two weeks ago.
I should have taken photos throughout the install!

[massacre]

Glad to hear you got them installed

[sly]

I used a 20 and it blew that!

Wow. You might need to upgrade the fuse holder and wire then. 30 amps needs 10 gauge wire. You might get by with 16 for a while, but if you use the horn for more than just a quick toot, you may fire the wires.