no power to horn

[robv]

i have a 1970 mustang and for some reason my horn stopped working.
before anyone says it, it is not the contact ring or any kind of brushes. i have removed the steering wheel disconnected the 2 wires that are there. i traced one all the way to the front where it plugs into the horn and checked continuity and it is fine. the other i am guessing is the power but no matter what position the key is in when i check the wire with a tester i get nothing. another weird problem that i noted is that the hazard lights no longer work either. the directionals both work fine and no fuses are blown.

so my questions are 1) where does the power wire go to i can not track it and 2) anyone have any guesses or things for me to test?



thanks!


UPDATE #1: while i was driving just now i was flipping the hazard switch and off and sometimes it would come on. so with this 2 weird things. the lights didn't flash they just stayed solid and when this happened and i hit the horn it would take a bit and then honk but super lower and quick and the hazards would dim.



UPDATE #2: while checking the power again i noticed something strange. at first it thought there was no power getting to the hot lead for the horn but then upon closer inspection i saw that the tester was indeed lit but so dim i could barely see it. i traced the wire down the column o the plug and disconnected hat and it is still dim from there. i can not for the life of me figure out where the wire goes from there. anyone have any ideas why the power to that wire would be so weak?

 

[soutex]

I don't have a 70 but I looked at the prints on line and the yellow +12V wire comes from starter solenoid through the column plug and provides your horn power. The other side of the circuit is the Blue with Yellow stripe wire which also passes down to the column plug then out to engine compartment to the large multi contact plug that also contains the wiring for your lights. Through that plug to the horns and then to ground. You can download the print here: Vintage Mustang Wiring Diagrams

 

[soutex]

Oh yeah, the other part of the question. I have seen these types of symptoms before and they generally come down to two troubles: partial ground or a plug that was pulled apart then pushed back together and the male part of the plug pushes the female receptor up the plug so that there is little to no contact by the male plug. Check column plug and then the multi plug under the hood. A quick check would be to get a 6 or 7 foot length of 16 Gauge wire and solder an alagator clip on each end. Attach one side to the wire at the horn and the other on one of the multi meter probes. Then take the other multi meter probe and touch it to blue - yellow wire either at the column plug or horn contactor under the wheel. Switch the scale to ohms setting and check for continuity. If you have continuity (zero or nearly zero ohms). If you do then the wire to the horn is good. Your problem is on the other side of the circuit.

Good luck.