Air horns.

Vehicle maintenance and repair questions in here please for all questions relating to Cars, Vans etc.

Moderator: Moderators

Post Reply
trooper
Senior Member
Posts: 175
Joined: Fri Sep 06, 2013 9:54 am
Has thanked: 21 times
Been thanked: 3 times

Air horns.

Post by trooper »

WoW! :? Do I have a problem? I've always fitted a set of air horns that I've swapped from car to car over the years, except, to my present motor, simply because the horn is very difficult to access. Anyway I arranged for my local garage to do the job & decided to make sure they were okay first, not having had them working for app 2years. Did the necessary with temp wiring etc & they didn't work? So now I'm investigating. I removed the trumpet air linkage to the compressor & made a temporary connection from it to the car battery. The comp ran but didn't sound as I'd expected it to. Hmmm! Now on the comp, the connections are clearly marked + pos & - neg which is naturally, how I've always wired them up using a relay & never had a problem. So I connected the wires again & put my finger over the comp outlet to the trumpets, it was "sucking" instead of blowing!!! As they've always worked when I've had them on my previous cars I was stunned. So because of the comp sucking, I reversed the polarity & it ran as it should.
Over to you for possible reasons. Don't forget, I'm linking the comp direct to the car battery to test it.
User avatar
Someone-Else
Senior Member
Posts: 10768
Joined: Sat Sep 01, 2012 6:03 pm
Has thanked: 22 times
Been thanked: 1823 times

Air horns.

Post by Someone-Else »

so whats your question?
It runs run way not the other, swap the supply round
Fret not, a forum is a collection of opinions. Above, are mine.


Working on anything electrical? have you got a multi meter? why not? Would you hit a nail with a shoe?

If gloom had a voice, it would be me. :mrgreen:

:idea1: How to post a picture on this forum Click here

Video of how to resize / rotate pictures can be found on This page
User avatar
ayjay
Senior Member
Posts: 9327
Joined: Wed Nov 17, 2010 5:51 pm
Has thanked: 446 times
Been thanked: 1600 times

Air horns.

Post by ayjay »

trooper wrote:
Sat Nov 07, 2020 3:50 pm
I've always fitted a set of air horns that I've swapped from car to car over the years, .....
Did the horns by any chance begin life on a car with a positive earth system?
One day it will all be firewood.
trooper
Senior Member
Posts: 175
Joined: Fri Sep 06, 2013 9:54 am
Has thanked: 21 times
Been thanked: 3 times

Air horns.

Post by trooper »

Good question ayjay & thanks for your input. These were bought new & there's no mention on the fitting instructions of a pozzy earth.
User avatar
Someone-Else
Senior Member
Posts: 10768
Joined: Sat Sep 01, 2012 6:03 pm
Has thanked: 22 times
Been thanked: 1823 times

Air horns.

Post by Someone-Else »

I would say you are overlooking the obvious.

The direction a D.C. motor runs depends on the polarity. So if you swap the polarity round the motor will run in the opposite direction.
It looks like someone has connected it the wrong way round, so as I said earlier, if you find the compressor is sucking instead of blowing, it really is a simple case of swap the polarity round, because the motor is running in the wrong direction.
Fret not, a forum is a collection of opinions. Above, are mine.


Working on anything electrical? have you got a multi meter? why not? Would you hit a nail with a shoe?

If gloom had a voice, it would be me. :mrgreen:

:idea1: How to post a picture on this forum Click here

Video of how to resize / rotate pictures can be found on This page
Post Reply

Return to “Vehicle maintenance & Repair”