Horn

[Mart]

i took off my steering wheel i while back and when i put it bk together, the horn wasnt workng.checked all the wiring and it seems fine so i checked the fuse.

the fuse had gone and my mate had a higher amp fuse and put it in and the horn still doesnt work.

is it because the fuse is of a too high rating?

[geordie_aaron]

may have shagged the wiring then, because the fuse (20amp init?) 9only allows a certain voltage through before it blow (saving wires + horn) but if you put a higher rating fuse in your tell the fuse to let more voltage than the wires + horn may handle.....

 

sound like you've fried sumit

[Prostheta]

Check your hazards - if they don't come on then you've blown the fuse (fuse 20 in the box).

 

Aaron, just to clarify - a fuse is designed not for voltage, but for current. It will blow when current exceeding the fuses rating passes through the wire. They work using Ohms law as they are linear discrete components (at least, linear till they blow). True, a fuse will more than likely blow if a larger than normal voltage is present across the fuse, but only if the wattage exceeds the melting point of the fuse wire.

 

To illustrate:

 

W=VI

 

A 12v/10A fuse is designed to blow at:

 

W=12*10=120w

 

Given an over-voltage of 20v This fuse should also blow at:

 

W=VI

I=W/V

I=120/20=6A

 

Anyway, lesson over :-)

 

I had the a problem with my horn not working (heh) when I replaced the standard MK5 airbagular wheel with a MOMO wheel and Puma boss. The horn contacts were shorting out inside the boss (solved with some cardboard!!) and fuse 20 decided to die on me, taking out the hazards in the process.

 

As you say Aaron, putting in a fuse of a higher rating will allow that circuit to work normally, albeit without protecting it from most current or voltage faults. It may be that the air compressor motor coil shorted (died!) and burnt out causing the fuse to blow. Disconnect the horn and see if a 12v feed from another circuit gets it working again - stuff the horns with rag though because they're LOUD at close quarters.

[Mart]

if it is the coil, ill get one at the scrappy monday, cheers mate

[Prostheta]

I'm having a problem with the battery not keeping charge at the moment - i'm tempted to just replace the battery out of course but it's no assurance that it actually IS the battery. Similarly, I would test the horn first before you go replacing it with another horn. It might end up not working, same as this one if the problem lies elsewhere :-)

[geordie_aaron]

I'm having a problem with the battery not keeping charge at the moment

 

Snap its been happening over the last 3/4 weeks, i've replaced starter motor, te battery is a 6 month old diesel BAtt, and the alternator is from a diesel...... java are just fooked after 10 years bday haha