Horn only works when car is off...

- M
- M. G. Devour
  
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posted
19 years ago

Tue, Apr 27, 2004 1:14 AM

Hi all,

1990 Cavalier with 4 cyl., auto, no air or power anything... Very basic car.

Strange issue: The horn will blow with the car off, but with the ignition on and/or the engine running the horn circuit doesn't work.

The horn relay is good, the horn is good. With the key on and/or engine running the relay doesn't click.

Thoughts?

I'm willing to bet one of the answers will be: Check grounds... If so, let me ask in advance *where* will I find the ground(s)I need to check?

Thank you, folks.

Mike D.

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- George Kowal
  
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posted
19 years ago

Tue, Apr 27, 2004 3:51 AM

I wouldn't normally susupect the grounds in this case, because usually the ground side of the horn circuit is the fact that the metal horn gets screwed onto the metal of the car. That's something that doesn't change whether your key is on or off.

I'm thinking there would be a problem with the ignition switch, since what I envision is with the key at off, there is voltage running to the horn relay, while when the key is on, there is no voltage available to trigger the horn relay.

I would verify that at the horn relay socket with a meter or light bulb.

You may not have to replace the switch if you don't want to, if you supply another source of +12 volts to the horn relay that is on while your ign key is in the on position.

GK

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- eddy eagle
  
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posted
19 years ago

Tue, Apr 27, 2004 4:24 PM

Cars are so sophisticated these days. The RRM module has determined that you have used the horn at inappropriate times and were in danger of causing a road rage incident. Therefore, it has given you a horn 'time-out'.