Hi guys,
Does anyone know how much our dual horn setup draws per horn ? The only proper fuse I see is in engine bay fuse block 2 number 6, for some reason shares with headlight high beams 30A.

Has anyone taken off the bumper and has some what clear pics of the stock horn wiring?

I really don’t see the point of using a harness if the wiring is good enough, I need 20A per new Marco horn, so currently it’s 30A, anyone knows how many amps the high beams are?

I have enough extra wires in the engine bay, so I am not a fan of more unless I have to. My plan is to put a 40A or 45A or 50? Fuse in there and just use the stock wiring.

Thanks

Update pics and what I have found out:

so see the plastic bit that attaches to the horn with the green wire, anyone know how many gauge that is ?

anyways so the body of the horn grounds to the car and the green wire is positive. In case anyone is wondering how to wire these things up. At first I was leaning towards using factory wiring I did hook it up and it does work but, depending on what the gauge is I might do a relay.

theres a formula out there and table which tells you if you have however many amps you must have this gauge and that length etc.

 

No one? Come on throw a guy a bone here lol

 

You shouldn’t use higher amp fuses than what’s rated. If it’s 30A, then use 30A or lower. The wires might not be able handle the heat and melt.

If you’re not using high beam and the horns at the same, I don’t see any issue with both on a 30A circuit.

Try it out and see if the 30A fuse holds. You can check the amp draw if you have an amprobe and have access to the 12V wire to the high beam.

 

Based on my experience with adding two additional OEM Lexus horns to the horn circuit of the 2000 LS400 I sold in 2014, I suggest powering your new horns from the car battery using a relay and trigger the relay from one of the existing horn positive wires. Maybe it's a coincidence but my horn pad, which also included the airbag, failed a few days after I added the extra horns. After I had the horn pad/air bag assembly replaced - expensive! - I rewired the extra horns using a relay.

I tend to think that my horn pad failing must have been a coincidence since the factory installed horns should have also been powered by a relay. Regardless, I'm not going to do anything like that again without using a relay. Aftermarket relays are inexpensive and very compact and it's simple to run the wires.

You might be able to leave your existing horns in place and install the new ones if you can find a place to install them. You might like the volume of having 4 horns. You could even run the relay trigger wire through a dash mounted on/off switch similar to the city/country horn switch on a Mercedes S-class.

Here's a link to a photo of the extra horns on my 2000 LS400 that I posted back in 2011: https://www.clublexus.com/forums/att...front-view.jpg

 

Posted some updates on my horn install more photos to come and videos when finally done.