Interesting.
According to the box, the current draw of the TM80 Compact Stebel horns is 11 amps. It looks like the Magnum version draws 6 each, so 12.
I just looked in the garage to see if I could find my old ones, but I suspect I may have disposed of them.
If I could measure the resistance, I could have calculated how many amps they pull.
For clarity purposes, I’ll measure the resistance of a brand new disc horn vs a snail horn and report back in the morning.
https://www.beal.org.uk/automotive/horns-reversing/universal-horn-12v-high-tone.html
vs
https://www.beal.org.uk/automotive/horns-reversing/trumpet-horn-12v-low-tone.html
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On my new ones the resistance is zero between both terminals and both terminals and the earthing/mounting bolt.
According to MX5 parts, this is normal for electromagnetic horns but wouldn’t apply with a compressor.
If you have a crimping tool, make a short fly lead with a 6.3mm female insulated spade at one end and a ring terminal at the other. Doesn’t need to be more than a few inches long, just long enough to reach from the terminal to the mounting stud.
I’m not aware that they are polarity conscious, so it wouldn’t matter which terminal (unless it’s marked pos and neg)
The single OEM wire fitted to the remaining terminal.
The hardest part if this job is gaining access to the horns.
I did mine by removing just the half a dozen screws on the front edge of the under tray.
It’s tight and you’ll get covered in grazes, but do-able
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Thanks but from what I can tell, this is actually unnecessary as the mounting bolt acts as an earth anyway and is shown as such on the wiring diagram on the box,
I think there are two terminals in order to be able to take the power to just one horn and then onto the other one, as they are often mounted adjacent to each other.
I have a ‘snail’ horn fitted to my other car using the existing wiring, it’s been on for over two years without any problems.
But if you want to fit a relay watch this video.
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