New horn push. Am I missing something????

A little while ago I installed all new switches and controls along with a new factory wiring harness. Everything worked except the horn push. There is power in on the purple but no power out on the purple/ black wire. If I go to the main cable connector in and join the purple and the purple/ black wires then the horns will sound. I blamed the new horn switch, so I ordered another one fromm Moss. Hooked it all up, and the same problem. Power in on the purple but no power out on the purle/black when I depress the horn push. Bypass the horn push and connect the purple and the purple/black wires and the horns will sound. Do I have two new bad switches, or am I missing something???
Thanking you all in advance. David

Sounds like a ground problem to me.

I am at the house and don't have a schematic close by so you will have to look that one up.

Jack

I assume you are talking about your 78 or 80 B. Are you bypassing at the horn push
connections and using all the horn wiring circuit, except the push? If yes the push is
probably bad. The wiring diagram shows a fuse in the purple/black wiring between
the horn push and the horns. But if you are bypassing only the push and the horns
work it should be a bad horn push

If you have a multimeter remove the push, set your meter to the ohms scale and
check between the push contacts, it should have 0 or near 0 ohms when the button is
pushed, infinety when released. If no meter you could make a circuit with a light bulb
and some wiring with the horn push in series. Hook the circuit to a battery charger or
a battery. When the push button is pushed the light should come on. If it passes that test
it should be good.

Clifton

New switch, actually two new horn combo switches. Power to the purple, push the horn push nothing out. Cross the purple to the purple/black and horns sound. Could they both be bad. 1978 MGB. Purple /black lead out to Limeys relays so little current is used. Like I said by pass the horn push and horns sound. Could I have purchased two new bad horn pushs??

Test the voltage out of the horn push where the purple/black attaches. That should tell you whether the push is OK.

Wayne

What!!! Am I an idiot!! There is nothing out!!

You may not be getting enough amps to the horn. When you put a meter on the switch looking to voltage it can show a full 12 volt but there may not be enough amps to operate the horn. When you bypass the the switch more amps can be drawn. The horn wire has a multi pin block which I think was in the front right side. The block may be dirty or corroded. Jack also hit the ground idea which can cause a lack of current flowing through the horn. Try this. Disconnect one of the horns and hit the switch if it works not enough amps if not try switching it. It realy sounds like you've got a weak curcuit. Clean the grounds and connectors to the horn and also you engine ground which may be, if it's like mine on the tranny mount. I made another for the engine which is another thing to try. Run a jumper wire from the body to the engine and see what happens. I wouldn't say it's your switch though.

Everything is absolutley brand new. New wiring harness. I have two new switches. Limeys relays on the horns with lots of power to the purple. When the horn stalks as in two switches are depressed there is no current coming out of the purple/black to the relays to the horn. By pass the switch, and the horns sound. This is with both new switches. The only thing at this moment that I am thinking of is I got two new bad switches from Moss.

If you short the purple & purple/black wires together and the horn sounds, it seems you either have 2 bad switches or bad connections. I'd check the connector for corrosion and see if ii is seating all the way. If you have an ohm meter you can check the switch for continuity.

It sounds like two bad switches from your tone...

Like has been said at least three times above jump the wires that you hook the switch to if there is no sound suspect your fuse / relay / horn. If the horn honks suspect your switches.

It's been several years since I was inside that switch but, as I recall, there is a little thingy (to be technical about it) that sits in the end of a spring. If the thingy gets dislodged the horn won't work. Someone on here (maybe Wray?) had a much better explanation on here back then. Maybe he (or whoever it was) will see this thread and comment....