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Discussion Starter #1
Here's the deal:

  • horn did not work when I bought car
  • replaced steering column (w/ a tilt)
  • replaced horn relay
  • replaced horn contact ring
Here's the symptom:

push horn button and horn stays ON.

dis-connect horn wires at horns

remove horn cap and depress contact on horn contact ring. You can hear the horn relay click on AND off.

However, when you re-connect the horn wires to the horns, the horns are still blasting, albeit intermittently. Take a screwdriver and tap on horn relay and it stops.

So, to me, it sounds like a defective horn relay. But is it? It's brand new. What else can I look for, before I go and buy another relay?

Is there a "leak" on the low-side of the relay (the horn button) that's causing the relay to flutter? I did remove the contact ring completely, so it's not the contact ring.

Sorry for the long post, but I wanted to give all of the details.

thanks - Mark
 

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All a relay is is a switch that uses and electromagnet to move the switch on. There is a spring to keep the switch open (off). When current (electricity) is applied the electromagnet pulls the switch closed (on). Get one of these as a test relay:

http://www.allelectronics.com/make-a-store/item/RLY-351/12V-SPDT-30-AMP-AUTOMOTIVE-RELAY/-/1.html

Then read this:

http://www.autoshop101.com/trainmodules/relays/101.html

The reason the your horn relay has 3 connectors is that the case ground is the 4th connection. Instead of a wire going to ground, the horn relay merely needs to be attached to the chassis thereby grounding it. A quick check would be to make sure you are getting a good ground from the relay case to the chassis. You can test this with a DVM (digital volt meter). If you don't have one, get one for $5 from Harbor Freight.

alan
 

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Discussion Starter #3
A quick check would be to make sure you are getting a good ground from the relay case to the chassis. You can test this with a DVM (digital volt meter). If you don't have one, get one for $5 from Harbor Freight.

alan
I would think a bad ground would keep it from sounding, not keep it on. Since the spring keeps the circuit open, perhaps the spring is weak?
 

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In your post you said the horns sounded constantly until you tapped the relay. Take a test light with alligator clips and hook one end to the red connection and the other end to the black connection. You can disconnect the leads to the horns temporarily so they don't sound. If the light goes on and off in concert with you depressing the horn button, then in all likely hood your relay is bad. But I would test it with the $2 relay from Allelectronics before I spent the big money on a new relay.

If the light stays on when you release the horn button on the steering wheel, you have a problem in the steering wheel section.

alan
 
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