Any Auto Electrician Here?

[subie]

Hi guys..

after connected the wiring for horn .. every time i press the horn botton it, blew the fuse (10amp) then, put 15 amp in it and blew again..

what wrong in the wiring ? any short-circuit ? what to look and how to fix?

thanks in advance

[GeeTR]

Horn relays? I'm getting de ja vu

Im no auto-elec, but fuses pop when they pass their current limit for an amount of time. If your popping 15amp ones instantly (and there should 10's in there) Then theres a pretty strong short circuit somewhere.

I suggest the power wire for the horn, is touching the chassis somewhere. Tracing can be very tedious. At the relay, see if there continuity between the power (that goes to the horn) and the chassis. If there is, its def a short circuit.

Good luck, i hate finding shorts through harness wiring

Edited February 12, 2008 by GeeTR

[blind_elk]

But it seems it's not until subie presses the button that the short occurs to blow the fuse.

Might I suggest that the action of pressing the horn is enough to depress the live contact on the button so that it makes contact with the steering column, causing the short.

Make sure the live contact onto the button is fully covered (insulated).

[Jmaac]

Depends on the state of the circuit, either naturally open or closed. As above you'll have to trace back the wires and look for any potential problems.

Check the connections at the s/wheel, fusebox (inc. relay) and at the horn itself. Is it the stock oem s/wheel?

[subie]

after market steering wheel

I'll go and check all the connection from steering wheel column, boss kit and the horn button

thanks guys

Edited February 12, 2008 by subie

[GeeTR]

But it seems it's not until subie presses the button that the short occurs to blow the fuse.

Yah, even with a dead fuse, wouldnt the relay still click shut? (assuming the s.wheel switch trigger is good to go) Replacing fuse and hitting the button causes the power to to the chassis throguh a short circuit, killing the fuse?

I would think a quick test would be to test the power pin at the relay end with the multimeter set to continuity, or resistence. If touching the pin and the chassis proves a result..then uv got a S/C

Im just thinking out aloud here, could be wrong

Edited February 12, 2008 by GeeTR

[QWK32]

Yah, even with a dead fuse, wouldnt the relay still click shut? (assuming the s.wheel switch trigger is good to go) Replacing fuse and hitting the button causes the power to to the chassis throguh a short circuit, killing the fuse?

I would think a quick test would be to test the power pin at the relay end with the multimeter set to continuity, or resistence. If touching the pin and the chassis proves a result..then uv got a S/C

Im just thinking out aloud here, could be wrong

Yeah thats right. most horn buttons switch a ground signal or -ve signal to a relay, which then switches the +ve feed to the horn, it gets its -ve side from the chassis. its the +12v feed to the horn that is the line with a fuse in it.

and yes the best way to check if its a short on in the wire to the horn is to, disconnect the horn, and do a continuity test between the +ve feed to the horn (on a relay usually pin 87 on a bosch relay), and a chassis ground. if you get continuity its the wiring to the horn which will be mainly in th engine bay.

edit: just went and checked the relay and the horn relay pin to test is pin number 3, nissan number thiers differently.

Edited February 12, 2008 by QWK32

[subie]

Thanks guys,

problems solved .. the horn was faulty that cause the short-circuit!

cheers

[GeeTR]

Another happy customer