An easy one

[mgbcca]

My '75 MGB had air horns (Fiamme) fitted which have stopped working. The wiring for the air horn relays is a bit puzzling - a fused hot wire (red) splits to power the relay which appears to be grounded back though the horn button wire (purple/black I think). The relay then is connected to the compressor and on to ground.

Anyway, I have bought the proper horms - one high, one low. I am now trying to figure out the wiring. If I wire up one horn with the fused live (red) feed to one terminal and connect the other terminal to the horn-push wire purple/black, it works fine. If I add the second horn in series they won't sound (just splutter a bit).

Here's the question - am I right in thinking that the horns are supposed to wired in parallel? That is, each will get a hot feed and both get connected to the horn-push wire (which I'll need to split).

Help please.

 

[adam90009]

kinda sounds like my problem. i have 2 horns and i can oly have one hooked up at a time because if i have them both hooked up they make a kalunk! sound

 

[Dave Russell]

MGB,
The horns should be connected in parallel.

Did you remove the relay? If so, the horn push won't last very long without it.
D

 

[Bob Claffie]

Standard horns eat up a lot of amps, not sure about the air horns/ compressor. Sounds like you are not getting enough power or the grounds are poor. Like the man said don't skip the relay! Bob

[ 04-08-2004: Message edited by: Bob Claffie ]</p>

 

[Bruce74B]

Hook the horns up in parallel and clean or replace ($10) your horn button brush in the steering wheel hub. If the the horns are good they should work fine if the ground is solid... through the purple/black wire to the horn button. Also check the wire where it goes into the steering column (where it hangs under the dash) to make sure that it has not been "kneed" too much and possibly stretched thin.

I don't know about a '75, but my '74 has no relay.

Bruce

 

[piman]

Hello MGB.
you had a set of air horns with the relay switching the power to the air compressor which is earthed. Simply take the air compressor feed to one terminal of the new horn and then loop that terminal to the second new horn. (As long as the existing wiring is large enough to feed both, else replace with a larger wire. ( I can't tell you what size as I'm not conversant with American wire gauge)
Connect each horn to earth from the second terminal. That should do it.

Alec

 

[mgbcca]

Thanks for all the advice - I should be honking happily soon...