Fitting AIR HORNS
Discussion
Hello Mini people, I wonder if any of you nice folks can give me some help with fitting of air horns to my girlfriends mini cooper (classic). I can't work out how to wire the switch and the relay and the compressor together. Girlfriend is impatiently foot tapping in the garage.....would really appreciate your advice!! :confused:
Connect the existing horn wires to the coil contacts of the relay.
Connect a fused 12v feed (from the fuse box is good) to one of the switched contacts on the relay, the final contact goes to the compressor '+'
Connect the '-' on the compressor to an earth point, or just to the mounting screw would probably do.
Relays usually have a little diagram on them showing you which pin is which, but if not the pins should be numbered as follows:
the coil contacts are 85 '-ve' and 86 '+ve'
30 and 87 are the switched contacts ie power in and out.
Normal relays are not sensitive to polarity so it doesn't matter which way round they go, but some have a diode in them to suppress voltage spikes so it pays to connect the coil contacts up the right way just in case! (the diode will go bang if you get it wrong)
>> Edited by Dino42 on Sunday 26th June 00:15
Connect a fused 12v feed (from the fuse box is good) to one of the switched contacts on the relay, the final contact goes to the compressor '+'
Connect the '-' on the compressor to an earth point, or just to the mounting screw would probably do.
Relays usually have a little diagram on them showing you which pin is which, but if not the pins should be numbered as follows:
the coil contacts are 85 '-ve' and 86 '+ve'
30 and 87 are the switched contacts ie power in and out.
Normal relays are not sensitive to polarity so it doesn't matter which way round they go, but some have a diode in them to suppress voltage spikes so it pays to connect the coil contacts up the right way just in case! (the diode will go bang if you get it wrong)
>> Edited by Dino42 on Sunday 26th June 00:15
Sure you can take a live feed from the starter solenoid - just make sure you put a fuse in the wire.
Oh yeh and take it from the always live side of course, otherwise it only works when you're cranking the engine
To use a separate switch I'd recommend taking a switched live feed (maybe from the radio or back of the dash somewhere) thro' the switch and to the relay coil terminal and then to earth.
The power side is the same as before.
Bear in mind that air horns use quite a lot of power so use thicker 28/030 wire for the power feeds.
14/030 is fine for the switch/relay coil side.
Oh yeh and take it from the always live side of course, otherwise it only works when you're cranking the engine
To use a separate switch I'd recommend taking a switched live feed (maybe from the radio or back of the dash somewhere) thro' the switch and to the relay coil terminal and then to earth.
The power side is the same as before.
Bear in mind that air horns use quite a lot of power so use thicker 28/030 wire for the power feeds.
14/030 is fine for the switch/relay coil side.
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