AIRHORN - RELAY- HELP

orle, May 7, 4:04pm
some friends car the air horn was not going the other week. relay was clicking but no power was coming out the line to the air-horn motor. so i replaced with a new relay and it worked again. now a week later and its doing the same thing again! you press horn and relay clicks but no power comes out for airhorn motor

help thanks

jasongroves, May 7, 4:07pm
Loose connection!
Wrong amp rating on the relay!

jono2912, May 7, 4:09pm
Sounds like somethings causing it to pull too much current thru the relay

orle, May 7, 4:09pm
same relay that came with original horn kit. it did work now same problem as before. just wonder if dud relay or other faults can cause this problem

jono2912, May 7, 4:10pm
Have you checked insulation! Loose connections etc!

orle, May 7, 4:17pm
on which wire! relay has 4 wires. permanent power in, power down to relay when horn is pressed, and 2 original horn wires. when you disconnect original horn wires the relay dont click so the circuit must be working.

i can only think of it as another stuffed relay.

orle, May 7, 4:51pm
a relay has 4 terminals

87-permanent power to relay - works
86-horn button earth - works
85-horn button power into relay - works
30-power to airhorn motor - no power but relay clicks when horn button is pressed

im only a mech and not a electrician but i cant see it being anything else but the relay again.

a18a, May 7, 5:02pm
probably another relay failed. this happened lots to me with my air horns. a bigger relay and the problem was gone

orle, May 7, 5:05pm
the original air-horn kit lasted like 5 years until the relay was broken. this new relay lasted 1 month with very little use. its a 30amp relay, not sure what the original relay was.

jono2912, May 7, 5:23pm
That's probably your problem.
Increase the relay size and see what happens.

pup2, May 7, 5:25pm
I would check the current draw to ensure your relay is big enough. If not, get a bigger one, if it is, just unlucky

andrew241, May 7, 5:45pm
Have you cheaked the earth on the air compresser!

orle, May 7, 6:28pm
there is no power coming out of the relay. i dont see how checking the compressor earth is relevant. but yeah i put power direct into terminal 30 power to compressor and works no problem

bigfatmat1, May 7, 7:45pm
if you have power in and on 30 or 87 and no output on 30 87 depending how wired and it clicks relay is at fault. replace it. If you want to know why it stopped pull the relay apart and inspect the contacts if they are blowen or melted away you have a short possibly intermittent. if the arevery black with deep pits in them chances are your drawing to much current through them possibly compressor about to sieze or tired.

bigfatmat1, May 7, 7:46pm
I always inspect old relays before replacing to see if its wear and tear or a possible fault elsewhere

orle, May 8, 6:55am
the relay has a fuse on it. would not have thought a short can bugger the relay without setting off the fuse

bigfatmat1, May 8, 7:05am
depends what size the fuse is.

pete_iam, May 8, 10:49am
30 amp which is the rating of the relay

bigfatmat1, May 8, 2:33pm
30 amp fuse is to high for air horns lol pull the relay apart and inspect it instead of drip feeding info and asking questions that may not be relivent

pete_iam, May 8, 6:19pm
eh the relay fuse is to protect the relay not the airhorn.

jono2912, May 8, 6:38pm
Sigh.

bigfatmat1, May 8, 7:06pm
The fuse should be rated at 130% of the air horn current.fuse is there to protect from after the fuse holder to the air horn, relay included it is not rated to What the relay says on it. Have you inspected the contacts yet!

pup2, May 8, 7:30pm
hey mat, want some ice for that head of yours. You've been banging it against the old brick wall for a while now lol

skin1235, Jan 28, 6:09pm
why not lube the compressor, like they're supposed to be, you know couple of drops per month, allowing for it now being so dry inside it will absorb near 20mil of oil without showing on exhaust
it will improve the air pressure, and decrease the amps required to run it therefore stop it burning out relays