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MG MGB Technical - Horn button shock

Had to replace the original horn, signal, dimmer switch because the plastic was deteriorating. Never had this happen before but now, when I push the horn button I get a good shock. Before I pull the switch to see where the short is, I thought I'd see if anyone has a fix.
Ted Mack

Never had a shock off 12 volts!! The horn button only earths out the horn circuit anyway.
Allan Reeling

Never had a shock off 12 volts!! The horn button only earths out the horn circuit anyway hence carries little current. Just check your connections to make sure you haven't put live through the horn button.
Allan Reeling

What age is the car?

Some later models were switched live.
Dave O'Neill 2

Thanks Dave, 1978 onwards were switched live, as you say. Why you might ask??
Allan Reeling

Regarding Dave O'Neills comment about some later models having a live switch can produce a shock produced by the on/off function - kind of like a transformer due to the on/off cycle. You can cure the shock situation by putting a relay in the circuit. Cheers - Dave
D.W. DuBois

Or a diode in the horn wire would fix it as well
That's only if you are getting the shock on release of the horn activation

Some relays actually have a diode built into them to stop electrical noise when switching off

willy
William Revit

You will almost certainly get a shock from 12v touching a circuit that is switching an inductive load such as the horn, and horns do take quite a bit of current. Even on the pre-77 models where the button puts out an earth to the horns, one side of the switch contacts is at 12v when the button is released.

What year is this? And what type of horn push? To get a shock you must be touching a metal component, that is connected to the circuit that is being switched.

paulh4

This thread was discussed between 04/06/2017 and 08/06/2017

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