trouble shooting horns

[ianfox]

I'm trying to find out why my horns won't work via the column stalk switch. So far, I've discovered the purple/yellow at the horns is live, and the earth is grounded. From what I've read, this is the reverse of what I should find? At the relay, both plain purples are live, and the purple/yellow are not, even with the horn switch pressed. Additionally, if I ground the spare male terminal on the relay (red circle in pic), the horns operate?? Not sure which leads to check at the column connector, but the purple/black has no power when switched? Lastly,, as a bodge to pass our Roadworthy Inspection, do you think if I rig a push button switch to earth that relay tab, I risk releasing all kinds of smoke?

[DJT]

Section of wiring diagram for horns and relay. Purple/black is earthed via the horn push. Can you hear the relay click when the horn button is pushed (ignition on)? If not, it could be the relay is u/s.

B092C69F-4A90-49B7-BF94-2180B35185F0.png

[ianfox]

Thanks Dave. I don't hear the relay click. Can I just replace it with a standard type relay? It may also be the switch, because I think I should see voltage at the purple/black when active?

[Ian928]

I just had the same problem, it was the switch in the column.

On my diagram (Colored bought Off E-bay) the codes for the relay was wrong, live was on the other pin than on the diagram.

I grounded directly from the pin on the relay and the horn worked, that made me sure the switch was the problem.

[bullstarz]

When mine didnt work i did all the test with the multi-meter, got 12v to the horns but no noise. Power direct to the horn and they worked. Tried a light in place of the horns and that went on and off as i pressed the horn. Took ages to think back to the basics of electrickery, Open circuit, short circuit and the one one I overlooked high resistance. Yes the was high resistance in the wires, they were nearly 50 years old and had corroded. While you got volts there was not current so not enough power to make even a mouse squeak.

[trunt]

I just had the same problem, it was the switch in the column.

On my diagram (Colored bought Off E-bay) the codes for the relay was wrong, live was on the other pin than on the diagram.
.

Prospero? the big laminated one?

[DJT]

The diagram in the ROM has the following colours/terminals combination on the relay:

PY - C1
P - C2
P - W2
PB - W1

Screenshot 2020-07-02 at 13.58.52.png

[Ian928]

Prospero? the big laminated one?

Yes, see pictures of relay and diagram.

[DJT]

Looking at the photo above in #8, it looks like the PB wire in #1 is doubled up with the P on C1 whereas it should be on W1.

[trunt]

Yes, same error on mine, swap C2and W2 and it works!

also that interior light switch is wrong.. light switch was wrong, couple of things were not named correctly

a few wire colours were different, but that can be expected.

But having said that Its nice and BIG.. I just always cross ref. to the ROM.. but apparently thats wrong as well. see the radio supply thread!

[RogerS]

Same issue with mine, all checked out, turned out to be the stalk, the feed enters the bottom of the stalk from the column, it is attached to a metal spade at the base of the stalk that can not be seen. my feed had detached from the spade which was very difficult to see until you pulled on the wire.

Roger S

[ianfox]

Solved thanks guys. Turns out it's handy if you can read the labels on the relay terminals I was planning to substitute another relay, but discovered the P/B was in the wrong spot. I put it back to W1, and we have contact. Thanks for the help fellas.

cheers
Ian