New horns

I picked up a set of the 4 tone Cadillac horns for my ‘05 Tacoma. Do I need to wire these up through a relay triggered by horn button or just use the existing wiring as it is?

 

Relay, use or splice into factory horn wire to trigger relay.

 

The factory Taco wiring is iffy for powering 4 horns. I have 8 Cadillac horns with 1 Bosch relay powering each group of 4 horns.

 

I used the existing wiring, but ran a ground wire from each one to a metal chassis point to ground them. Mine did not work without the separate grounding wire.

 

8 Horns!

But I Agree. Use a separate relay fused properly and triggered by the truck harness.

 

Yep, women spill their coffee and drop their phone when they blow the stop sign and I'm heading for their door.

 

They probably poop their panties too!

 

Relay for sure. Love my General Lee Dixie horn.

 

I did the 4-tone Cadillac horn for my truck as well. A long-time bucket-list upgrade for sure!

I mounted two horns on the driver's side, and two on the passenger's side, trying to balance between rigidity of mounting vs. obstruction of airflow to the radiators.

If I recall, the OEM horn circuit is on a 10A fuse, switched on the high side via a relay in the engine-bay fuse box.

If believe that 20A (total) were recommended for the four-horn upgrade. So I guess the rule of thumb is 5A per horn... but to be clear, I've never tested the actual current draw of any or my horns.

For my install, I elected to run the two driver's side horns from the OEM wiring to the original horns, having replaced the two OEM connectors with their Cadillac counterparts. Make sure to get the polarity right, because the Cadillac horns are made out of metal and ground through their body. Ask your seller, or test with a multimeter to be sure.

I mounted the other two horns on the passenger side, and ran a new 10A circuit to power them via a second relay in my aftermarket fuse box. Because I was already out of fuse slots there, I used the style of relay with a built-in fuse socket.

I ran a set of 16GA wires from one of the driver's-side horn connectors to excite the new relay, so that the passenger-side horns are triggered in unison. 16ga is overkill for triggering a relay, but since the OEM horn circuit was fused at 10A, I didn't want to risk undersizing any part of the circuit.

Essentially, I now have two 10A horn circuits, with two tones per circuit. The second pair are triggered via the first.

I am not a very aggressive driver, and I don't use the horns a lot. The few times I have though, always brought a smile to my face. They aren't overwhelmingly louder than any other car horn, but their unique tone easily ranks among the most American sounds of all time.

I'll upload photos if I can find them. Good luck!

 

Can’t imagine eight horns. Thanks for the info/instructions. I will make sure I use a relay.

 

Thank you for that diagram. I think that’s what I had in mind, use the original wiring to just trigger a relay for the new horns. Tested the horns and they really do sound like a train. Excited to get them mounted up.